There will be a game of citizenship poker played in Canberra this week with political careers at stake.

MPs from both sides could be referred to the High Court and there will potentially be a round of by-elections contested perhaps in March next year.

Prime Minister Malcolm Turnbull has outraged Labor by threatening to refer Opposition MPs to the High Court to have their citizenship questions settled.

By the end of this week, it will be clear how many people will have to have their citizenship status and, more importantly, their eligibility to stay in Parliament tested.

Senators have already filled in and lodged the forms to start the process and those family histories are due to be released today.

MPs tracking down family histories for documents

The form requires each MP to declare the place and date of their own birth, as well as each of their parents and all four of their grandparents.

That stretches back to 1860 for Queensland LNP senator Ian Macdonald, whose maternal grandfather was born in South Australia 157 years ago.

Senator Ian Macdonald's citizenship form, showing birth dates of his maternal and paternal grandparents. ( Supplied )

Senator Macdonald is relying on family records and the website Ancestry.com to establish the birth dates and places of his grandparents in the mid to late 19th century.

Tracking down the relevant information, especially for grandparents, has prompted some parliamentarians to schedule pre-Christmas visits to elderly relatives to find the relevant documents.

Labor chief whip Chris Hayes found the records for generations of his family going back to his great grandfather tucked carefully inside the family bible.

Chris Hayes found his family records inside a family bible. ( AAP: Alan Porritt )

But for others, like ALP senator Pat Dodson, no copy of his father John Dodson's birth certificate from Tasmania in about 1912 can be found.

The level of detail being made public has some MPs anxious, particularly when information like mother's maiden names are so commonly used to keep identities safe.

But others have embraced the process: Labor senator Don Farrell is providing a family photo to accompany the form.

His family picture shows his parents at their wedding flanked by each of their parents (the grandparents he names on his citizenship register form).

Don Farrell had to unearth this family photo to track down dates for his documents. ( Supplied: Don Farrell )

It shows Senator Farrell's maternal grandfather was born in Pontefract in England but he says advice from the UK Home office was that he had no entitlement to UK citizenship.

Deja vu: One Nation pushed for similar exercise in 1999

Eighteen years ago, One Nation senator Len Harris pushed in the Senate to try to force politicians to undergo the same sort of genealogical exercise that they are in the midst of this week.

His move was in response to One Nation's Heather Hill being found to be ineligible because she had not renounced her British citizenship.

His bid was resoundingly rejected by the major parties nearly two decades ago.

"We will have no part of what I think is a pretty half-baked, dubious and perhaps ill-conceived procedural device that is proposed today," Labor senator John Faulkner told him.

Labor's Robert Ray argued it was unreasonable to reverse the onus of proof of eligibility.

In 1999 Robert Ray argued it was unreasonable to reverse the onus of proof. ( AAP: Mark Graham (file) )

"The basic point is that we do not have to prove, other than by giving our word, that we are properly here," Senator Ray said at the time.

"If we are improperly here, it is up to someone else to prove it.

"Not only is it up to someone else to prove it; they can put some of their money up to prove it, just to test themselves."

But the pressure of seeing a string of politicians already ruled out by the High Court has seen all sides of politics agree this time.

Not only do they have to provide their family history, but the form also demands other relevant details including adoption, IVF or assumption of citizenship by marriage.

Those intimate personal details will soon be available on parliament's citizenship register.