Wallaby legend Michael Lynagh believes a lack of depth lies behind Australia's post World Cup slump.

Michael Cheika's men return to Twickenham on Saturday for their Rugby Championship finale against Argentina in their first match at 'headquarters' since a World Cup final defeat by New Zealand just over a year ago.

Few would have forecast then that loss would mark the start of a run of six straight defeats for Australia, albeit all the games concerned were against the world champion All Blacks and a resurgent England coached by former Wallaby boss Eddie Jones.

Australia head into this weekend's match in London having won just twice in eight games, with the initial optimism engendered under Cheika, who took charge following the shock resignation of Ewen McKenzie in October 2014, now a thing of the past.  

"We thought that under difficult circumstances, the team and Michael Cheika performed very well to get to the final," Lynagh, 52, told AFP in an interview on Friday at the London office of financial media firm Dow Jones Corporate, where he works as the managing director for Europe, the Middle East and Africa.

"They played good rugby and it's not that much different to the team that's been trotted out this year," explained former fly-half Lynagh, a key member of the Wallabies' 1991 World Cup-winning side.

Lynagh, whose 911 points in 72 Tests remains an Australia record, added, however: "There's been some issues. (David) Pocock hasn't played a lot of games and he was arguably one of the players of the tournament at the World Cup.

"The England games we were down to our fifth inside centre which, when you are a nation such as Australia that struggles with depth, is not great and it's the same now. 

"When you look at them, (Matt) Giteau, (Kurtley) Beale, (Matt) Toomua and (Christian) Lealiifano are all out."

- 'Struggle' -

Last week's 18-10 defeat by South Africa was typical of Australia's recent problems, with the normally efficient Wallabies failing to make their pressure count. 

"When you get more than 50 percent of the ball, you look at the Wallabies and you think they are going to score a lot of tries -- that was the case at the World Cup -- and they normally win games," said Lynagh.

"But it's been a real struggle this year to score tries. Whether that's because oppositions have worked them out, whether they don't have enough versatility in their armoury, we've yet to see. 

"But we are in a rebuilding phase. We lost six in a row there but all six of them to the number one and number two teams in the world (New Zealand and England) so it's not too bad."

Argentina head into Saturday's match with just one win, over South Africa, in this season's Rugby Championship.

But Lynagh insisted the Pumas, defeated by Australia at Twickenham in last year's World Cup semi-final, will still be one of the "teams to beat" at the 2019 edition in Japan.

Right now, he reckons they are paying the price for the first season of the Jaguares team -- the Argentina side in all but name -- in the Super Rugby club competition.

"They had a tough Super Rugby tournament -- it was their first time in there and I think players dealing with the travel and it's a long season and it's always the same group of players," Lynagh said.

"They wanted to incorporate more teams and I think that's diluted the product a little bit. 

"I can understand wanting Argentina to be there, but when you've got an extra South African team, another Australian team and a Japanese team who play home games in Singapore as well. More is not necessarily better.

"But Argentina play a pretty good brand of rugby. They are pretty dangerous and they've been very close (to more wins) and they'll go close again on Saturday.

"I think that with teams in both these championships, they will really benefit and they will be one of the teams to beat at the next World Cup."

Television analyst Lynagh, who overcame a life-threatening stroke in 2012, finished his playing career with London club Saracens, now the reigning English and European champions.

Saracens boss Mark McCall has led criticism of last week's England training camp -- which included a judo session-- that saw Wasps flanker Sam Jones break his leg and Bath wing Anthony Watson fracture his jaw. 

"It's just ludicrous," said Lynagh. "You can't have a guy playing for Saracens or whoever on a Sunday, then going doing judo sessions on Monday and Tuesday and then playing Wasps on a Saturday. It's just too much."

Source: AFP