South Africa are facing a fitness crisis ahead of the Rugby World Cup.

Coach Heyneke Meyer told South African media on Wednesday that the situation was so concerning that some players would be left behind when the Springboks travel to Argentina for their non-championship warm-up game next week.

"The thing I've said from the start – and I take the responsibility, it's not the franchises fault – is that our fitness levels are not where they should be. I've said it from day one," Meyer said.

"If you want to outplay Australia and New Zealand you have to be fitter than them."

While he has stuck with his best players for the final Investec Rugby Championship match in Durban on Saturday, Meyer said some of them would not be making the trip to Argentina in order to concentrate on their physical preparation for the World Cup.

"The plan is going to be to give some other guys a chance, and the other guys can stay and just do unbelievable amounts of fitness, probably for two weeks. That's what we need," he said.

Even with the extra fitness work needed, Meyer said things had improved for the side since they first came together to open their season with a game against a World XV.

"Nobody gave us a chance after Super Rugby. I truly believe we've closed the gap. It's very, very close no between the top sides," he said.

"With another three or four weeks of unbelievable fitness and training regimes, I truly believe we can be at our best going into the World Cup," he said.

Meyer solved his issue over where to play centre Jesse Kriel in the wake of Jean de Villiers' return to centre by moving Kriel to the wing. Handre Pollard had been doubtful for the game but has been included.