What's really frightening about the current All Blacks is the inability of some awesome players to make the Test team. Take the out-half position, where Andrew Mehrtens appears John Hart's favoured choice over the brilliant Carlos Spencer. Now that's scary.

You could go further. Many international teams would be only too happy to have Simon Culhance wearing their number 10 jersey, but he's watching this tour unfold on his television back in New Zealand.

As it is the Mehrtens v Spencer out-half debate has generated quite a fuss back in New Zealand. It is usually the case when two outstanding out-halves emerge in the same era. We only have to recall the Campbell-Ward fuss back in the 70s, when the two names seemed to become synonymous with each other.

For some reason, out-half rivalries seem to polarise opinions like no other position. Perhaps it's the nature of the number 10 shirt. They're usually the star turns. They usually take the kicks, call the shots and bring very distinctive styles to the position. What's more, there's rarely room for compromise - putting one at first centre generally doesn't work. Hence, nearly everyone has an opinion on which is better.

It is, apparently, a bit like that in New Zealand, where for sheer prolificness there's never been a rivalry quite like it. Mehrtens is the boy with the golden boot - he was literally portrayed as such on the cover of NZ Rugby last summer after averaging 17 points a game for the All Blacks in his first two prodigious seasons at Test level.

Somehow, his timing was perfect. An effervescent dressing-room prankster and mimic, known to join in in Mexican Waves by crowds during lulls in a match, Mehrtens is an outgoing, chatty type more befitting the new image of the All Blacks. A big movie buff, he can regale/irritate teammates by remembering every line from films such as Pulp Fiction.

He is a sharp lad. He won a scholarship for calculus while at college, possesses a near photographic memory and reputedly never forgets a telephone number on seeing or hearing it.

Although actually born in Durban, South Africa (where his schoolteacher parents extended a holiday to see game reserves into a four-year stay) the Mehrtens jeans had it, for his grandfather was an All Black and his father represented New Zealand juniors.

Despite no national recognition at schoolboy level, a meteoric rise through the New Zealand under-19s and Canterbury teams culminated in an eve-of-World Cup debut against Canada in 1995 - which he marked with a world record first Test haul of 28 points.

Laurie Mains duly threw him straight into the All Blacks' World Cup opener against Ireland (another 18 points) and Mehrtens delivered another world record by requiring only five Tests to accumulate 100 points.

While relatively slight, Mehrtens - quick, with good hands and tactically well ahead of the posse - proved himself ideally suited to the All Blacks' new running game. But he could kick too, both off the ground and out of hand. His individualistic, smooth style is notable for the way his whole body seems to go through the motions. He compares it to golf - at which he is a 10-handicapper - once saying: "It's all about weight transfer".

Mains wrote in his autobiography: "If we'd set down on paper, after the frustrations of 1994, all the qualities we sought in the ideal first five, we could not have improved on Andrew."

There was only one blip: the missed dropped goal at nine-all in the World Cup final against South Africa with five minutes remaining. That apart, Mehrtens could do little wrong - scoring 291 points in 17 Tests over two seasons. Wary of late dropped goals, he instead called the last minute move which yielded the winning try against Australia in Brisbane. There seemed little danger of anyone rivalling his throne.

The along came cheeky Carlos. Though not as erudite in front of a camera or microphone, Spencer is even more flamboyant and seemingly cocksure of himself on a rugby pitch. Liable to do anything at any given moment with his sleight of hand and party tricks, Spencer is an even greater running threat.

Spencer is perhaps not as metronomically reliable a place-kicker, nor as sound a tactical kicker as Mehrtens. And curiously, despite being physically bigger and stronger, he is not as reliable in the tackle, though he's even quicker.

With Mehrtens beset by a variety of injuries over the last two seasons Spencer's profile rose. He led the way in the Auckland Blues' march to the 1996 Super 12 title with 87 points, and followed that up with eight tries in Auckland's march to the NPC title, including an incredible, record-equalling five-try display in their 59-18 semi-final win over Otago.

Though he performed relatively poorly as one of Mehrtens' understudies in the tour of South Africa, Spencer left an indelible impression in the New Zealand Barbarians' defeat of England at Twickenham a year ago this week.

Coming on as a substitute for Mehrtens, Spencer immediately livened up everybody with his irreverent, off-the-cuff moves. His chip and catch try, celebrated with a trademark pointing to the crowd, along with a couple of penalties and a conversion copper-fastened their 34-19 win.

Yet, during Ireland's development tour last summer I was reliably informed that John Hart was more concerned with Spencer's first two kicks for position. Both were charged down, re-affirming Hart's view that Spencer takes comparatively long out of the ball. It's a view substantiated by some New Zealanders on the basis that Spencer has been slightly spoiled by domineering Auckland and Auckland Blues packs, and the long pass of Ofisa Tonu'u.

But he kept making an impression, a big impression. In the Blues' benchmark, unbeaten Super 12 campaign this year Spencer was joint seventh in the try scoring table with seven tries: only wingers and Christian Cullen outstripping him.

Yours truly was privileged enough to see one of those tries, an outrageous foot-rush from a snappily taken drop out which Dennis Bergkamp would have been proud of. Picked on the shadow All Blacks side in the Test, he was a trifle guilty of showboating, yet his individualism illuminated a predictable afternoon. I must admit, I am a fan.

Mehrtens' injury jinx duly gave Spencer his chance this summer in the first Test against Argentina. Matching Mehrtens' 80 per cent-plus place-kicking ratio (his six out of seven, 20-point haul in the 35-32 defeat of South Africa in Johannesburg betrayed an equally cool nerve) Spencer went on to plunder 101 points in his first five Tests.

In his first seven Tests Spencer scored five tries amongst his 147 points. Then he was injured toward the end of the NCP championship, a recuperated, revitalised Mehrtens steering Canterbury to the title after a semi-final win over Auckland as Spencer gloomily watched on. It's a fascinating sub-plot to the tour.

So Mehrtens appears to be coming here as first choice. They deny they are rivals, and it must be difficult for them. Meantime, back in New Zealand the debate continues. As for John Hart, don't envy him too much. He could close his eyes and stick a pin on his options for number 10.