We'd send a letter to Bali nine too, says Howard

Prime Minister John Howard said the Australian government would provide the lawyers for the Bali Nine with a similar letter to the one sent to Schapelle Corby's lawyers if a proper request was made.

The government had a duty to provide information to Australians charged with offences overseas, he said.

Five Australians were arrested at Denpasar Airport in Bali on April 17, and four at Hotel Melasti, Kuta Beach, allegedly preparing to import several kilograms of heroin into Australia.

The federal government sent a letter on Friday to the Indonesian lawyers for accused marijuana smuggler Schapelle Corby, in the attorney-general's name.

The letter outlined allegations about the involvement of Australian baggage handlers in drug smuggling.

Mr Howard said he would do the same for the so-called Bali Nine.

"Yes, if it were a proper request," he told Southern Cross Broadcasting.

"They are entitled, like Schapelle Corby, to a presumption of innocence.

"I couldn't do anything other than respond to any request -- legitimate, fair request -- for information.

"Our job is to help Australians who are charged with offences overseas, to provide (them) with all the information and assistance that we properly can.

"But it's also my responsibility to ensure that we respect the judicial system of a friendly neighbour."

Later, Treasurer Peter Costello said while he wanted Corby to receive a fair trial it was important Australia not interfere in the Bali justice system.

"You can imagine what would happen if a foreign country came in and told the Australian courts how to manage a trial," he told Southern Cross Broadcasting.

"They might be very resistant to that.

"So you've got to be careful enough to recognise that this is a sovereign country with its own justice system."

Mr Costello said the Australian government was always willing to do what it could to help Corby put her case to the Bali court.

"We did facilitate a prisoner coming out of Victoria to go and give evidence in Bali," he said.

"That was a pretty big step and the government was willing and able to assist.

"But you've got to remember this, Bali is not Australia.

"There's some people that think Australia somehow runs the Balinese system. It doesn't.

"And just as the Australian courts wouldn't be heavied by the Indonesian government, you've got to remember Indonesian courts can't be heavied by the Australian government."

- AAP