England's tactics have been defended by Stirling Mortlock but the Australia captain has tipped South Africa to put an end to their challenge in Saturday's World Cup final in Paris.

Mortlock, still pained by his side's 12-10 quarter-final loss to England almost a fortnight ago, said the defending champions had played intelligently by adopting a forwards-orientated game dominated by stout defence.

However, he warned England's gameplan must change if they are to become the first nation to win back-to-back tournaments by beating the Springboks.

"England have played smart and played to their strengths," Mortlock said. "Their tactics have been pretty consistent the last three times and I wouldn't think they would change too much.

"They have had a lot of knockers, especially during this World Cup operation, and I think they have proved them all wrong by continuing to win.

"Try-scoring opportunities have been hard to come by and decisions have had a big impact on the results, so they have played smart and that's why they are in the GF (grand final)."

However, the Wallaby has warned England that their simple but effective gameplan will not be enough to knock over the Springboks.

"South Africa have the ability to overcome those tactics," he said. "I can't go past South Africa. They have got a quality team, playing some good footy.

"It will be very tight but I'd say they will come out the winner."