The citizenship saga engulfing federal MPs will spill over into the new year as both sides continue to fight over referrals.
Labor MP David Feeney is the latest to be referred to the High Court to clarify his citizenship status, because he could not find documentation relating to the renunciation of his UK citizenship back in 2007.
Senator Katy Gallagher has also been referred, but the opposition is holding out sending any of its other members with questions over their citizenship.
Despite being a vote short to refer Labor members, the coalition is maintaining pressure on the crossbench and Labor leader Bill Shorten to take action himself.
Deputy Liberal leader Julie Bishop wants the likes of Justine Keay, Josh Wilson and Susan Lamb referred.
"They must refer themselves or Labor must refer them," she told ABC radio on Thursday.
Ms Bishop says a number of Labor MPs are in the same position as Liberal MPs the opposition are questioning.
She used the example of chief government whip Nola Marino who has a letter from the Italian embassy saying she was not an Italian citizen, just like Deputy Labor leader Tanya Plibersek who has a similar letter from Slovenian authorities.
"Why would they refer one and not Tanya Plibersek," she said.
"The governments of other countries know whether or not they're citizens and if there is a letter from the government of another country that should be enough."
Fresh from fighting his own by-election having had to renounce New Zealand citizenship by descent, Nationals leader Barnaby Joyce believes government MPs should also be referred if there are questions about their citizenship.
"Any person who believes they shouldn't be there should put themselves forward," he told the Nine Network.
Manager of Opposition Business Tony Burke insisted his colleagues took reasonable steps to renounce their citizenship and in the case of Mr Feeney, he has been self-referred.
"David Feeney knows it's unacceptable, we know it's unacceptable," he told Sky News.
Leader of the House Christopher Pyne said the government is unlikely to refer any further MPs with citizenship doubts to the High Court this year unless it can win over an independent MP's support.
The government is short one vote, with John Alexander soon to face a by-election in Bennelong.
The High Court is due to go on a summer break from December 15 and is scheduled to return February 5.
