It is 10 years since Wales won six consecutive internationals but to repeat the feat they will need to defeat New Zealand at Wembley next week, a prospect that looks remote following events at St Helen's yesterday.

Wales's desire to play a fast, open game manifested itself immediately, but it was rugby by numbers, a robotic programming which meant that, instead of playing for position early on in the wet conditions, they ran from improbable positions, too often for the sake of it.

Wales showed more tactical awareness in the second half but against a side of New Zealand's menace, the match would have been long lost by then. Tonga, indisciplined and unable to hold on to the ball, posed little threat throughout.

It was always going to be a question of how many Wales would win by but for all their possession, they only scored one try in the first 40 minutes and the 6,589 crowd grew restless, impatient and critical, even booing the referee for penalising the Tongans.

Tonga were fortunate that their relish for giving away penalties, particularly close to their line, did not see them concede at least one penalty try. They did not fall apart, however, in the second half when the game was beyond them and rallied to claim the final try of the match.

Wales led 23-0 at the interval. Gareth Thomas scored their first try at the start of the second quarter, but their second did not come until four minutes into first-half injury-time when a lengthy siege of the Tongan line seemed destined to be unproductive before centre Leigh Davies forced his way over the line.

It was uninspiring stuff but Wales showed neater touches in the second period, Davies's delicate chip which yielded Thomas's second try a moment to savour and it begged the question why Wales had not used their pace out wide to chase the rolling ball long before.

The introduction of scrumhalf Robert Howley after 55 minutes made a difference: Howley, direct, enterprising and deliberate, increased the tempo and Wales scored three tries in 14 minutes, all well executed with space created behind. Tonga scored two tries by way of consolation but the rain inhibited them and it was only at the end, when the sun finally came out, that they extended a passage of play beyond two phases.

The real test comes next week. Howley looks certain to start but it is presence and power up front that Wales need: with the Quinnell brothers out of favour, there are few alternatives to yesterday's eight forwards and therein lies the problem for coach Kevin Bowring. "New Zealand are human," said Bowring, "as they have shown in their three matches on tour so far. We will have a go at them and nothing is impossible."