The Australian Government has been told it has an obligation to support the establishment of an international tribunal to prosecute those Indonesians involved in the 1999 bloodshed in East Timor.

The United Nations Secretary General is considering a tribunal following last week's aquittal in an Indonesian court of several officers allegedly involved in the pro-Indonesian militia riot, which killed hundreds of people.

The former head of the UN's mission to Timor, Ian Martin says Australia promised the East Timorese that justice would be done.

But he's worried many countries won't support a tribunal because they want to re-establish strong military ties with Indonesia.

I'm afraid there may be an attempt to pretend that these proceedings have been serious when unfortunately they've been anything but serious.