Australia's one-day batsmen are under mounting pressure to keep their places after a lacklustre series defeat to South Africa, captain Aaron Finch warned Monday, with a potential shake-up looming.

While the hosts won in Adelaide to snap a seven-game losing streak, they crashed heavily in Perth and lost again in Hobart by 40 runs.

None of the key batsmen performed consistently, although number three Shaun Marsh hit a fighting 106 in the decider on Sunday.

Finch admitted ‘we're all under pressure when we lose, no doubt about that’ and hinted at changes ahead of their next series against India, ranked two in the world, in January.

"Between the batting line-up not having got it right for a little while now there's going to be questions asked whether it's Maxi, Lynny, Heady, or myself or Stoin," he said, referring to Glenn Maxwell, Chris Lynn, Travis Head and Marcus Stoinis. "It's important that we really nut out the balance of the side and get that right over the next two months. We have to either adapt our game plan a little bit around the way the side structures up best or we slightly change our personnel to fit a style that we think can win."

Big-hitting Lynn was elevated to open the batting in Hobart in a bid to get quick runs on the board, but it failed spectacularly when he was out first ball.

Despite this, Finch said the powerful right-hander, a prolific scorer in T20Is, is likely to open again as Australia look for more aggression early in the innings.

"Yeah, it could be a long-term plan," he said. "It was an attacking option to put Chris at the top, to change him and Travis (Head), to put a couple of guys up there who can get us off to a flyer. It was an attacking move. If I had my time again I'd still do it."

Lynn, who has played 14 T20Is, is still developing in the longer form of the game, but showed his abilities in the second game of the three-match series by smacking 18 off the first four balls of a Kagiso Rabada over.

He was out on the fifth, but Finch said it demonstrated how he can turn a game.

"We saw it in Adelaide when he flicked the switch against Rabada in that over. Yes, he got out, but he changed the whole momentum of the game totally," he said.