Tony Abbott has admitted his full policy costings and savings will not be released until after the political advertising blackout, ensuring Labor cannot use attack ads targeting the policies in the final days of the campaign.

As the election campaign enters its final week, Abbott said the full costings would be released after the final policy initiatives were announced up to "the middle of the week". The advertising blackout takes effect on Wednesday night.

Abbott was speaking ahead of the Labor party's official campaign launch on Sunday. Later in the week, Kevin Rudd makes his final set piece pitch to voters on Thursday at the National Press Club in Canberra and could have the Coalition's full costings at that time.

But Abbott insisted there was no surprises for voters in his final costings.

"I don't believe the additional savings to be announced later this week will impact on ordinary Australians and I want to give people this absolute assurance, no cuts to education, no cuts to health, no changes to pensions and no changes to the GST," Abbott said.

Abbott also conceded that the Coalition's Indonesian boat buyback scheme may not purchase a single boat with the $20m fund he committed as a measure to stop asylum seekers arriving in Australia.

In the wake of criticism from Indonesia regarding the Coalition's $20m boat buyback scheme, Abbott softened his stance on the policy, saying it was simply a way of interrupting people smuggler operations.

Asked by the ABC whether it was possible that a Coalition government would "never buy a single boat", Abbott said "it is possible".

"A fund, $20m, would be available to our people on the ground in consultation and co-operation with the Indonesians to try to ensure the local villagers were working with us rather than with the people smugglers.

"We may not buy boats back but if we did have the opportunity to pay someone a couple of thousand dollars to stop a boat from being launched, when if that boat arrived in Australia it would cost us some $12m per boat to deal with people, that would be a shrewd investment."

Over the weekend, Abbott also came under pressure over his comments that the Muslim womens head dress, the burqa, was "a very confronting attire".

Abbott made the comments while he was defending a Liberal candidate's comments on the issue.

Ray King, Liberal candidate contesting the treasurer, Chris Bowen's seat of McMahon in western Sydney, had suggested women should stop wearing the burqa, which allows Muslim women to cover their head and face.

"Frankly, it's not the sort of attire that I would like to see widespread in our streets," Abbott said on Saturday.

Keysar Trad, a spokesman for the Australian Federation of Islamic Councils, was critical of using the burqa issue in any political debate.

"The election should not be a debate about the burqa," he told the Sydney Morning Herald.

"Anyone who uses women's dress as an issue in politics is just showing his bankruptcy of policies."