Crossbench senator Derryn Hinch says details of a US social security number which has embroiled him in the dual citizenship debacle were leaked by a "close friend" who "doesn't like me".



Key points: Hinch still holds US social security card from working at SMH in New York

Hinch still holds US social security card from working at SMH in New York Says he "never held US citizenship"

Says he "never held US citizenship" Hinch still calling for independent citizenship audit of all parliamentarians

The Victorian senator will refer himself to the High Court after confirming that he still holds a US social security card from his time living in New York in the 1960s and 1970s, which could be a breach of the constitution.

Section 44 of the constitution not only bans anyone with allegiance to a foreign power from sitting in parliament, it also disqualifies anyone who is "entitled to the rights or privileges of a subject or a citizen of a foreign power".

Senator Hinch will now be the eighth parliamentarian to face a High Court ruling.

He told RN Breakfast the details of his social security number were given to the media by "a close friend" who was familiar with his case.

"Someone has done it, someone doesn't like me," he said.

Hinch got social security number while working in New York

Earlier Senator Hinch released a statement saying he would take his case to the solicitor-general and, "if necessary", to the High Court.

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But the influential crossbencher said he did not believe he was in breach of the constitution.

"I have never held US citizenship. I have never held a Green Card," Senator Hinch said.

"I do have a social security number because I worked for the Sydney Morning Herald in New York and automatically acquired one. It stays with you, citizen or not, until you die.

"I have not accepted the 'rights and privileges of a foreign power'. I paid a special social security tax for 10 years, on top of regular income tax, which makes me entitled to a pension. That's not a privilege. It's payment for that tax I paid in the 1960s and 1970s."

Senator Hinch also said he wrote to the US Social Security Department instructing them not to pay him a pension.

"In September last year, I wrote to the Social Security Department saying 'I don't want to be accused of double dipping, so please freeze my pension," he told RN Breakfast.

"I can't vote in the United States, I couldn't even work there without the right papers."

The influential crossbencher renounced his New Zealand dual citizenship before entering parliament — and has previously said he had "no sympathy" for "dual citizenship slackers" who have been engulfed by the controversy.

"I probably read that section [44 of the constitution] more than anyone — I looked at prison records that I have and all the angles but I never dreamed having a security number would be any problem," he said.

Senator Hinch was jailed twice for contempt of court while working as a journalist.

In 1986, he was jailed for 15 days and fined $15,000 after publishing the prior convictions of a Catholic priest who was facing sexual assault allegations.

In 2011, he was sentenced to five months of home detention for breaching a court order and revealing the names of two sex offenders.

Senator Hinch is also standing by his call for an independent audit of all parliamentarians over dual citizenship, despite the question mark now hanging over his own election.

"I still fervently believe that the Senate next week should again vote on referring each and every Member of Parliament to an independent auditor," he said.