The playing future of Australian opener Justin Langer is attracting fresh speculation after his father hinted his son may be close to retirement.

Langer has refused to say whether he will join Shane Warne and Glenn McGrath by quitting test cricket after next week's final Ashes Test in Sydney.

But Langer's father Colin told The Age newspaper his 35-year-old son was "not going to hang on for the sake of hanging on".

"He's been privileged to play for his country for 104 test matches," Colin Langer said.

"The way he's gone about his career has been a thrill for his family. To see the effort that's had to be put in, the effort no one really sees.

"To see what he's done to try to get fit for this series, it's just been unbelievable, the physical effort, the time he spends with his batting coach.

"People don't see all that, but we do."

Australia coach John Buchanan would not be drawn on Langer's future but paid a glowing tribute to the left-hander, who has scored 7,650 runs in 104 Test appearances and formed Australia's most successful opening partnership with Matthew Hayden.

"He's a tremendous character to have within the team with a set of values which he's admired for," Buchanan said.

"He believes in all the traditions of the game and, really, in many ways, he's the epitome of the baggy green cap."

Langer's position in the team was under threat from Phil Jaques before the series began but he silenced his critics with an unbeaten century in the first test in Brisbane to earn the right to choose the timing of his own departure.

Warne and McGrath both announced last week they would retire from test cricket after the Sydney test while Langer's West Australian team mate Damien Martyn quit after the Adelaide Test.