The Aussie attack worked hard in the absence of Gillespie and MacGill

Persistent rain washed out most of the evening session on day four leaving Australia just one wicket short of an innings victory.

Australia led by 224 after reducing the visitors from an overnight 87-2 to 272-9, but dogged knocks to tailenders Sean Ervine (53) and skipper Heath Streak (42 not out) added to the hosts' frustration.

Imminent victory may come at a high price, as the extent of injuries suffered by key bowlers Jason Gillespie and Stuart MacGill became known.

Scans after the third day's play revealed Gillespie suffered a tear in a left-side back muscle, while MacGill has a tear in his right calf.

Gillespie, MacGill in doubt for Sydney

"Given the nature of the injuries and the short amount of time between Tests, I guess that puts a cloud over their availability for Sydney," said team physio Errol Alcott.

Zimbabwe added 23 runs early on Sunday with the third-wicket stand between Mark Vermeulen and Stuart Carlisle reaching 99 runs.

THE OPTIMIST We have certainly not given up hope of saving this Zimbabwe coach Geoff Marsh More day four reaction

But, when Vermeulen was contentiously given out caught behind off Brett Lee for 63, Zimbabwe promptly lost five wickets for only 16 runs.

Paceman Andy Bichel (3-55) and part-time spinner Darren Lehmann stepped up in the corrosion of Australia's frontline attack to effect the capitulation.

Lehmann, whose figures of 3-54 represent a Test-best after 15 appearances, offered batting hero Matthew Hayden his third catch of the match when removing Carlisle for 35.

The end looked nigh for Zimbabwe when Streak joined Sean Ervine in the middle with the score 126-7.

Streak and Price will be hoping for more rain delays on Monday

But a determined 83-run stand between the two frustrated Australia, with Ervine bringing up his maiden Test half-century in his third match.

Bichel broke the deadlock when bowling Ervine for 53, paving the way for Andy Blignaut to form a meaningful combination with Streak (42 not out).

The tailenders added 38 runs for the ninth wicket before Lehmann had Blignaut stumped for 22, but Ray Price's (17 not out) arrival at the crease coincided with the heavens opening.

What appeared as passing showers developed into a heavy downpour, and almost two hours were lost before the not-out batsmen survived 40 minutes prior to the final deluge which saw stumps taken.

Australia: SR Waugh (capt), RT Ponting, AJ Bichel, AC Gilchrist, JN Gillespie, ML Hayden, JL Langer, B Lee, DS Lehmann, SCG MacGill, DR Martyn.