Mitchell Starc during day four of the Third Test match between Australia and South Africa at Adelaide Oval on November 27, 2016 in Adelaide, Australia.

After a long injury lay-off at the start of 2016, Mitchell Starc has returned to the Australian line-up fit and firing, and he says he's close to being back to his best.

Starc returned from a six-month break to play in Australia's tour of Sri Lanka during July-August this year, claiming 24 wickets over the three-Test series.

The left-arm paceman was to be rested ahead of the recent South Africa visit but was instead in a race against time to be fit for the series, after splitting open his leg at training which required 30 stitches and some time away from cricket.

14 wickets against the Proteas was second to Josh Hazlewood in the Aussie bowling charts, as Starc had to take more of a back seat throughout the series as he once again tried to find his rhythm.

Starc got more miles under his belt after being a key contributor with the ball during Australia's 3-0 ODI series win against New Zealand, and the 26-year-old is ready to make a big impact on the Test scene once again.

"I think I've still got some way to come," Starc said ahead of the opening Test in Brisbane on Thursday.

"There's been times when I've been pretty happy with how it's been going and there's other times when I think I'm away from my best.

"That consistency is still yet to come back, which is exciting that I can still lift my game a little bit.

"Hopefully it's going to come back in this series. But I'm happy enough with how it's been going."