Former Howard government minister Amanda Vanstone has lashed Tony Abbott over a proposal to strip dual-nationals of their Australian citizenship if they support terrorism.

Ms Vanstone said as a Liberal she despaired to see some in the coalition, including the prime minister, thinking it was acceptable to take away someone’s citizenship in the “blink of an eye”.

“What were they thinking?” she wrote for Fairfax Media on Monday.

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“No appeal, no judicial process, just a ministerial decision.”

The former immigration minister said the idea of ministers having the power to take away people’s rights, without appeal, showed a “profound misunderstanding of the western democratic tradition”.

“Cutting down our democratic protections to get at the enemy is profoundly dumb,” Ms Vanstone claimed.

She also criticised the way the idea was taken to cabinet without proper pros and cons being prepared by the department, saying it was “either lazy, sneaky or both”.

An explosive leak to Fairfax Media in recent weeks allegedly revealed widespread opposition inside Abbott’s cabinet to the idea from high-profile ministers Malcolm Turnbull, Julie Bishop, George Brandis, Christopher Pyne, Andrew Robb and Barnaby Joyce.

Despite this, Mr Abbott has pushed on, with political commentators speculating that the proposal may appeal to many Liberal and undecided voters.

Current immigration minister Peter Dutton continues to campaign for the power to take away the Australian citizenship of dual-nationals if they support groups such as Islamic State (ISIL).

Both people at home and abroad could be affected at his directive, so long as they were not left stateless, Mr Dutton has explained.

“Whether they’re here or they’re offshore, we will strip citizenship from them under this proposal,” he told Channel Ten on Sunday.

There have been 150 people identified in Australia as supporting fighters in Syria, by fundraising, training and preparing to join them.

Mr Dutton defended his power to make the decision instead of a court.

“We believe that … it’s a decision for the minister of the day, because we are elected by the people to make these tough decisions.”

Several of his front bench colleagues, such as communications minister Malcolm Turnbull, have publicly disagreed on this point.

Last week, the former barrister described the rule of law — the principle that laws not the arbitrary decisions of the executive branch of government should govern a nation — as the “genius” of democracy.

“The rule of law means that the law applies to everybody. It applies to all of us, it applies to big companies, little companies, it applies to the government,” Mr Turnbull said during a press conference last week.

“The genius of a democracy governed by the rule of law, our democracy, is that it both empowers the majority through the ballot box and constrains the majority, its government, so that it is bound by law.”