RAAF Air Marshal Angus Houston said Australia's F/A-18 fighters had been heavily involved in coalition strikes on the Medina and Baghdad divisions and in supporting US marines on the eastern flank moving towards Baghdad.

Houston praised the progress of the coalition's campaign and said the air strikes could have stripped Iraqi soldiers of the will to fight.

"I think we've seen spectacular developments overnight and the way the coalition forces have got past the Medina divisions and the Baghdad divisions and are now on the doorstep of Baghdad is truly impressive," he told ABC radio.

"A major reason for that is the fact that the two divisions were heavily engaged by air forces over the last week and they obviously attributed to an extent where they've lost a lot of their fighting capability and perhaps the will to fight.

"Over the past few days, those two divisions have sustained almost constant engagement by air forces delivering precision-guided munitions and those precision-guided munitions are very precise and they can be targeted against individual tanks, artillery pieces and so on.

"Essentially that campaign has been highly effective, probably as effective as any other air campaign in history because I don't think we've ever had as many precision weapons used against two formations like these two divisions."

But Houston warned there were still substantial Iraqi forces on the north and east of Baghdad that had not been targeted by air strikes.

"And they still probably have a reasonable fighting capacity," he said.

The Australian contingent of 2,000 soldiers, sailors and air force personnel, the third force in the US-led coalition, have played a small but the government says has been a crucial role in the conflict.

Its SAS troops, backed by commandos of the 4th Royal Australian Regiment have airforce, have been operating since the start of the war in a forward reconniassance role, well ahead of advancing US and British military.

Defence officials said Friday that Britain's Royal Navy has rushed an Australian-developed mine clearing system into service near the Iraqi port of Umm Qsar.

The system, known as SWIMS (Shallow Water Influence Mine Sweeping Systems) uses mini-magnetic dyads which are towed behind combat support boats to blow up magnetic mines, defence force spokesman Brigadier Mike Hannan told reporters.

A mini-dyad is a floating tube which contains high-powered, strontium ferrite magnets.

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