Australian Defence Minister Joel Fitzgibbon confirmed on Tuesday that four suspected insurgents who were arrested by special forces soldiers on April 29 were held for 24 hours in a compound occasionally used to house dogs. Dogs are considered impure by observant Muslims.

The soldiers' actions prompted strong criticism from the head of Australia's main Islamic group, the Australian Federation of Islamic Councils.

'It is quite appalling that the Australian soldiers are in any way caught up in the inhumane treatment of human beings - irrespective of who they are,' said federation president Ikebal Patel. 'I think it's quite despicable that something like that could happen and that the Australians are party to it.'

The revelation follows complaints by an Afghan soldier about mistreatment of the detainees, who were held in southern Uruzgan province following a battle with Taleban fighters. An Australian Defence Force inquiry last week found that medical evidence and witness statements did not support allegations of abuse.

Mr Christian Taubenschlag, a spokesman for Defence Minister Joel Fitzgibbon, said the minister would not be available to comment further on the incident Tuesday. But earlier in the day, Mr Fitzgibbon defended the soldiers' actions, saying the detainees were held in the most secure place available before they were transported to a detention center in the town of Tarin Kowt.

'Our people were patrolling far away from our main base in Tarin Kowt near one of our forward operating bases. They did detain people suspected of the worst and most atrocious acts. And they detained them in the most practical way available to them at the time,' he told Australian Broadcasting Corp radio.

Mr Fitzgibbon said that it was misleading to characterise the holding facility as a dog pen.

'They were in a compound I've had described to me as a walled compound which I'm sure is used for a variety of purposes,' he told ABC. 'I'm advised that the compound is from time to time used to hold dogs, yes. Dogs are a very important part of our operations there.'

Afghanistan's Ambassador to Australia, Amanullah Jayhoon, stopped short of criticising the actions of the Australian soldiers, but did say the reports were troubling.

'It is a matter of concern because ... it provides propaganda for the Taleban, and at the same time it is not good to treat a human being inhumanely,' he said. '(But) we have not launched any formal protest.'

Mr Bob Brown, leader of the minor opposition Greens party, described the incident as a 'big mistake.'

'For Australia to find itself keeping prisoners in dog kennels, dog pens - even overnight - is a big mistake,' he told reporters in Canberra.

There are 1,000 Australian troops in Afghanistan. -- AP