UPDATE: BATMAN MP David Feeney is the latest federal politician to resign over the dual citizenship scandal.
The Labor shadow minister resigned in a press conference held at 3pm Melbourne time. He declined to take questions.
Mr Feeney won the inner-city seat in the 2016 election with 51.03% of the vote. The Greens secured a 9.58% swing to the party in 2016 election.
His resignation has triggered a by-election in the marginal seat, which could see another Greens MP enter the lower house.
Want to know more about the dual citizenship saga? Read how it first began to unfold in late 2017.
EARLIER: LABOR MP David Feeney has failed to find any proof he renounced his dual UK citizenship as he prepares to face the High Court this week.
More than a month after Mr Feeney revealed he could not locate his renunciation, the Labor powerbroker told The Courier-Mail he had yet to receive any more documents from UK authorities.
Mr Feeney is due to face a directions hearing at the High Court in Brisbane tomorrow.
"At this time we have been unable to retrieve any more documents from the United Kingdom's archives," Mr Feeney said.
Asked whether he was likely to find more documents, Mr Feeney said: "That's a matter for British authorities."
It is unclear what the Victorian MP's defence will be if he is unable to find any evidence of his renunciation from the UK.
A spokeswoman for the British High Commission told The Courier-Mail: "British nationality law is complex, with a number of factors influencing eligibility, including date and place of birth and citizenship of parents.
"It's not possible for us to comment on specific cases."