Cape Town - Springbok legend Schalk Burger believes that the All Blacks have "issues" heading into the 2019 World Cup in Japan.

The 2007 World Cup winner, who has now retired from professional rugby, was speaking at a Laureus Sport for Good breakfast at the Southern Sun in Newlands on Wednesday morning.

It is the uncertainty around team selection, Burger believes, where the All Blacks have slipped.

Coach Steve Hansen has made the controversial decision throughout the Rugby Championship to play Richie Mo'unga at flyhalf while two-time World Rugby player of the year, Beauden Barrett, has been employed at fullback.

"If you swap across to the New Zealand in 2015 and compare it to now, they have got issues," Burger said.

"They don't know who is No 10 and who is No 12 or who is their loose forward combination."

There is also uncertainty for the world champions at centre, where Sonny Bill Williams continues to enjoy Steve Hansen's backing despite looking far from his best while, in the loose trio, there is also no clear indication of who between Ardie Savea, Liam Squire, Sam Cane or Matt Todd will partner skipper Kieran Read.

The half-back battle between Aaron Smith and TJ Perenara also has no clear winner at this stage while there are also question marks over who will start in the front row.

The Boks, Burger believes, have more consistency.

"I suppose that's where we've gained the most on New Zealand," he said.

"If you take our potential best squad at the moment you've got Beast (Mtawarira), Trevor Nyakane, Frans Malherbe, Pieter-Steph du Toit, Francois Louw, Duane Vermeulen, Siya Kolisi, Eben Etzebeth, Lood de Jager ... Handre Pollard, Damian de Allende, Jesse Kriel, Willie le Roux," he said, naming the players who were also part of the 2015 run to the World Cup semi-finals.

Burger is feeling optimistic about South Africa's chances in Japan, and he says much of that has to do with the sustained form they displayed throughout a triumphant Rugby Championship campaign that yielded a first major trophy since the 2009 Tri-Nations.

"The one reservation I had before this year - we always knew we could beat any side in the world - but was whether we could do it three weeks in a row because that's what you need when you get to the playoffs in a World Cup," Burger said.

"It's high pressure and you need to deliver quality no matter what the opposition. These last three weeks have shown that we've got it."

Burger was also asked what he felt had changed in the Rassie Erasmus, compared to when the Boks delivered arguably their worst ever couple of years under Allister Coetzee in 2016 and 2017.

"There is a serious backbone to the side now and you don't get the feeling that they are going to roll over," he said.

"It's definitely about work rate too. If you look at the way we played against Argentina (this past weekend) ... we kicked, we chased, we were competitive in all facets.

"Now you see average kicks becoming good decisions by the work rate that is put in ... that comes through a serious culture or mindset change to graft for each other."

Burger also believes it is important that the Boks under Erasmus have not abandoned their traditional strengths.

"We're a hard side to play and we've got a good set piece. We still play the way South Africans like to play: we're abrasive and we're big units. We're direct," he said.

"It helps when we try and emulate the All Blacks with the subtlety and the offloads and good execution, but I think this team has got an identity and they know how to go about winning games."

The Boks are in action again on Saturday when they take on Argentina at Loftus in a one-off Test, while their 2019 World Cup campaign begins with a massive clash against New Zealand in Yokohama on September 21.