Christopher Pyne has criticised the Italian citizenship process, in defence of his colleague Senator Matt Canavan who resigned from cabinet this week after discovering his mother had made him a citizen of Italy apparently without his knowledge.

Senator Matt Canavan's future will be decided by the High Court.

"On that basis Kim Jong Un could make us all citizens of North Korea and we'd all have to resign," the Defence Industry Minister told the Nine Network's TODAY Show.

"Quite frankly what is going on with the Italian government? They will make people citizens of their country without having a signed application form asking to be."

The High Court will decide Senator Canavan's future.

Mr Pyne says the court "needs to make some pretty clear decisions" about the dual citizenship fiasco and specifically "when you do or don't become a citizen of another country."

"I assume the High Court will recognise it needs to be decided expeditiously. I'm sure they will make some sensible rulings around it and that will give us a way forward," he said.

Senator Malcolm Roberts was frustrated in his efforts to get clarification of his situation from the British government.

"The Australian public are looking at this and thinking, this is the theatre of the absurd, and there has to be common sense approaches."

Labor's Anthony Albanese says he's confident dual citizenship isn't an issue for any Labor MPs.

"We check these things out. We have checked out all our people, they are all fine."

Today it emerged the citizenship crisis might implicate up to 20 MPs.

Meanwhile One Nation Senator Malcolm Roberts says he did not receive confirmation he wasn't a British citizen until December last year, five months after he was elected.

Senator Roberts, who was born in India to a Welsh father and an Australian mother, says he wrote to British authorities multiple times before the election seeking confirmation of his situation.

He says he received a form from British authorities on December 5 declaring he was not a UK citizen.

"I write again, again and again to the British and said I believe I am not a British citizen and just in case though - if I am - then I renounce it effective immediately," Senator Roberts told Sky News.

"Then I persisted and persisted and persisted. Then I got a formal registration of my renunciation."