Steve Waugh silenced his critics again on Saturday with a chanceless century against Bangladesh that showed he is getting better with age.

At a vintage when most players have already retired, the 38-year-old Australian captain shows no sign of slowing down.

His unbeaten 100 against Bangladesh was his 31st Test hundred and gave him a full set of centuries against every Test-playing nation, but Waugh said he still wants more.

"I'm still just trying to improve, just because you're a certain age doesn't mean you can't improve any more so for me it's about getting better," Waugh told a news conference.

"I just wanted to go out there and play well and if I don't think I can improve then I shouldn't be out there."

Waugh, now in his 18th year of Test cricket, briefly considered retiring after a lean run last season but says he has no thoughts of giving up now that he is back in form.

"I had a tough time last year but I overcame that...so I'm doing it for myself now more than anyone else," Waugh said.

"It is nice to overcome those tough times, every cricketer has them during their careers, and it's probably a little bit harder as you get older.

"But I'm just happy with the way I'm playing, I'm enjoying the game and being positive."

Waugh said he is proud of his feat of scoring a century against each of Australia's nine Test opponents but is not driven by records.

"Records and milestones will all be broken but it is still nice to achieve things and to score a hundred against every country is something I'm proud of."