Four Australian men have committed suicide after being caught up in an investigation into child Internet pornography that has resulted in more than 200 arrested and charged for 2,000 offences, police said yesterday.

Justice Minister Chris Ellison said 700 Australians were now under investigation in the country's biggest child pornography crackdown and up to 500 people could eventually be arrested.

The four men, one in Western Australia state, two in Victoria state and one in Queensland state, killed themselves after being interviewed by police. Two had been charged with pornography offences.

Police launched Australia's biggest child pornography crackdown on Thursday, raiding 400 premises and arresting hundreds, including police, teachers, clergy and a child-care centre owner.

Those arrested in Operation Auxin face offences ranging from sexual abuse, to downloading and distributing pornographic images to child sex tourism.

More arrests are expected, say police.

A 46-year-old electrician was found dead in his car at his home in Bunbury in Western Australia on Friday after he failed to appear in court earlier in the day. He had been charged with three counts of possessing child pornography.

In the southern state of Victoria, a prison guard's body was found in his car on Friday after he was interviewed by police a day earlier, said local media. Another man's body was found in Victoria after being interviewed by police.

In the tropical northern state of Queensland, a former police officer facing 46 charges related to child abuse computer games, was found dead last month in the first phase of the child Internet pornography investigation, Queensland police said.

The officer was relieved of his duties in June when the pornography allegations first emerged. The day before he killed himself, he was ordered to appear in court to face 46 charges.

The Australian child Internet pornography crackdown stems from a US investigation in February that produced 95,000 child pornography leads worldwide, say Australian police.

Police say US authorities, mainly the US Customs Service, called a meeting with Interpol in February and revealed Internet child pornography mainly from Belarus in eastern Europe.

Australian police have yet to examine 400 computers and other material seized in 400 raids in the past week.

Police said some people arrested had child pornography libraries with more than 250,000 images collected over three decades and what appeared to be home studios designed to produce child pornography.