Former Wallabies boss Michael Cheika joins Argentina in training camp ahead of Tri Nations

Former Wallabies coach Michael Cheika has answered a call from Argentina's Mario Ledesma as the Pumas prepare for the Rugby Championship.

Argentina have been joined in camp by Cheika, who will act as an advisor despite previously saying he would never coach against Australia.

Cheika's arrival at the Puma's training facility in Sydney created something of a stir but Ledesma was pleased to have him on board.

"The fact that Michael can now be at the training venue and in contact with the players is great," Ledesma said.

"He is very enthusiastic about the team, he transmits lots of confidence and belief."

Ledesma worked under Cheika at the Waratahs and at the Wallabies - with the Argentine the forward coach of Australia at the 2015 World Cup.

Ledesma left the Wallabies set-up in 2017 before coaching the Jaguares in Super Rugby and then Argentina.

Ledesma is out isolation after spending two weeks in a biosecure facility in Sydney.

He was among more than a dozen Pumas players and staff to test positive for COVID-19 last month before they travelled to Australia for the southern hemisphere tournament - which is now a tri-nations after South Africa's withdrawal.

Having being released from isolation, the Pumas will have a contested training session against a NSW Waratahs XV on Saturday, a warm-up Ledesma feels is necessary for his players as many of them have not played since March.

Argentina face New Zealand in their opener on November 14, and again a fortnight later.

"Friendly matches are so important for us," Ledesma said.

"Having the opportunity of playing at least three games before the debut against New Zealand, seems not too much but for us it is essential."

Argentina will face Australia on November 21 in Newcastle and in the final match of the Rugby Championship on December 5 in Sydney.