Bipartisan support for legislation to strip the citizenships of dual nationals suspected of engaging in terrorism has crumbled.

The Coalition and Labor continued to attack each other on Friday over the proposed legislation, which will come before the parliament next Wednesday.

Labor says it wants to see the legislation before coming to a final decision whether to support it or not, and accused the Coalition of playing politics with national security.

Labor immigration spokesman Richard Marles said the opposition supported such a simple change to the law but was still waiting for a briefing.

'The only thing we have seen from the government is a leaked question time brief ... for Tony Abbott this is all about the politics,' he told reporters in Melbourne.

'We support an updating of the Citizenship Act but we just want to have a mature conversation with a grown up partner about how we can do that.'

'It is all about politics - it is all about trying to engage in political point scoring around the question of our nation's security,' he said

Tony Abbott says the likely failure of court prosecutions against terrorism suspects is behind the government's push for new laws.

Asked why a court conviction should not be required for the minister to act, the Prime Minister told reporters in Cairns on Friday : 'What happens if they get off? That's the problem. We all know that there are evidentiary issues with prosecutions of people for offences abroad.'

On Thursday the PM seized on comments made by the Shadow Attorney-General Mark Dreyfus that citizens fighting with terrorist groups overseas should face trial in Australia, telling parliament Labor wants to 'roll out the red carpet' for terrorists.

A day later, the former head of Australia's domestic spy agency warned against imposing extra bureaucracy on intelligence agencies to oversee expanded powers.

Retired ASIO head David Irvine told a law conference in Sydney that beefing up accountability could be better achieved by giving more funding to the independent intelligence watchdog, the Inspector General of Intelligence and Security.

Immigration Minister Peter Dutton has dismissed concerns about new anti-terror laws, saying he'll take advice from a legal team before stripping the citizenship of suspects.

The Law Council of Australia says the laws, which will go to parliament on Wednesday, won't comply with the constitution unless they contain judicial safeguards.