Tasmanian Senator Jacqui Lambie said on Monday that she will stand down if urgent inquiries to the UK Home Office prove she is a dual citizen - possibly within 24 hours.

As recently as last week, Ms. Lambie was convinced that she had "no concerns" about being a dual citizen by descent because her father was born in Scotland.

"His father, my grandfather, came to Australia to enlist in the Army in fact," read the statement released by Lambie last week.  "As far as I'm concerned all their affairs are in order, as are mine.  A citizenship audit of all parliamentarians will clear the air once and for all which is why I'm supporting such a move 100 percent."

Meanwhile, the Coalition and Labor have reached a deal to end the citizenship crisis.  It would require MPs to declare their parents' and grandparents' ancestry by 1 December, provide details about how they have determined they are not dual citizens, and what they have done to renounce any foreign ties.