Australian Prime Minister Julia Gillard and Opposition Leader Tony Abbott on Friday agreed to amend caretaker government conventions, so that the three independent Members of Parliament can be given a Treasury briefing about the budget impact of Labor and coalition policies.

The independents - Bob Katter, Tony Windsor and Rob Oakeshott - on Wednesday asked for a Treasury briefing on the cost of all Labor and coalition policies over the next term as a prerequisite for talks about forming a minority government.

At a press conference, Gillard said the Department of Prime Minister and Cabinet had advised her that Treasury briefing on the cost of campaign policies, would require caretaker conventions to be amended.

The prime minister and Abbott exchanged a number of letters on Wednesday, Thursday and Friday about the issue, before he agreed to the changes.

"I am pleased to report that Abbott has generally agreed that the independents should be able to get the material that they seek, " Gillard told reporters in Canberra on Friday.

"I welcome Abbott's general agreement to that."

According to The Australian newspaper, the move is a significant backdown for Abbott, who had told the country independents that he was not willing for Coalition policies to be cost by the bureaucracy.

But in a similar backdown, Gillard has agreed to provide to Abbott more detailed briefings and figures on the national broadband network and the minerals resources rent tax.

Once Treasury had reached the end of that process, every Australian should have access to both parties' campaign promises Treasury information.

"Every Australian has access to the government's costings. Every Australian should have access to Abbott's costings done by Treasury," Gillard said.