Prime Minister John Howard has told Washington that any action leading to further delays would be unacceptable and would prompt him to demand the return of Hicks, 31, after being held for five years at the US base at Guantanamo Bay. Colonel Morris Davis has accused Major Mori of breaching article 88 of the US military code, which relates to using contemptuous language towards the President, Vice-President or Secretary of Defence.

Penalties for breaching the code include jail and the loss of employment and entitlements. Major Mori denied he had done anything improper, but said the accusations left him with an inherent conflict of interest. "It can't help but raise an issue of whether any further representation of David and his wellbeing could be tainted by a concern for my own legal wellbeing," Major Mori told The Age. "David Hicks needs counsel who is not tainted by these allegations."

Major Mori, who has been to Australia seven times, will seek legal advice. The issue will also have to be raised with Hicks when his legal team next sees him.

The Federal Government has highlighted Major Mori's work as proof of the fairness of the much-criticised US military commission system. However, Colonel Davis said Major Mori was not playing by the rules and criticised his regular trips to Australia. He said he would not tolerate such behaviour from his own prosecutors. "Certainly, in the US it would not be tolerated having a US marine in uniform actively inserting himself into the political process. It is very disappointing," he reportedly said.

"He doesn't seem to be held to the same standards as his brother officers." Hicks' lead defence counsel, Joshua Dratel, a New York attorney, said Colonel Davis' threats were the latest example of the "corrupt" system that will try Hicks.

Mr Dratel pointed to the former senior Pentagon official in charge of detainee affairs, Cully Stimson, who resigned last month after urging businesses not to hire law firms that had worked for Guantanamo prisoners. US prosecutors are under intense pressure to offer Hicks, a former kangaroo skinner and father of two, a plea bargain deal by the end of the month. Senior Australian Government members want Hicks to come home a free man, provided he agrees to a pre-trial plea of guilty.

Amid rising public anger in Australia about Hicks' long wait for justice and alleged mistreatment, any Hicks trial risks becoming a public relations disaster. He is to be the first person to appear before a military commission. The world's media will be focused on the case, including al-Jazeera and other Middle Eastern outlets.

They will hear graphic testimony of abuses and torture by US guards and interrogators. It will involve a man, Hicks, whose alleged offence pales alongside the serious accusations made against alleged senior al-Qaeda leaders at Guantanamo Bay. Prosecutors have dropped three charges against Hicks — attempted murder, aiding the enemy and conspiracy to commit war crimes. There is now only the lesser charge of providing material support to a terrorist group. That charge did not exist for non-US citizens when Hicks was arrested.