A stalemate over citizenship referrals threatens to prolong well into next year the constitutional crisis sweeping Federal Parliament, as Labor leader Bill Shorten refuses to refer three of his MPs in doubt to the High Court.

With the numbers on the floor of the House of Representatives tied while Liberal MP John Alexander fights a by-election, the Government was unable to use its numbers to send to the Court of Disputed Returns Opposition MPs who held dual citizenship when they nominated for last year’s election.

In an attempt to break the impasse yesterday, Labor said it would agree to refer the MPs in doubt, but only if four more coalition MPs who it said had provided inadequate documentation were also included.

Amid calls from independent MPs for the two parties to agree on a list of MPs from both sides, the Government heaped pressure on Mr Shorten, saying the coalition had already done the right thing by referring five of its MPs and senators for a ruling. Four of the five have been forced to resign.

“This is where we have the Leader of the Opposition now twisting and turning in his own incompetence and dishonesty,” Prime Minister Malcolm Turnbull said. “Tit for tat is no substitute for justice.”

But while Labor is refusing to budge on three MPs in doubt — Josh Wilson, Susan Lamb and Justine Keay — it yesterday referred Victorian MP David Feeney and ACT senator Katy Gallagher for a ruling.

Mr Feeney, who has been unable to locate any documents to prove his claim of renunciation a decade ago, is at high risk of losing the northern Melbourne seat of Batman to the Greens if a by-election was held next year.

Senator Gallagher said that while she believed she was in the clear, she accepted her case needed to be clarified given she did not receive confirmation of her renunciation until two months after nominations closed.

With the two parties unable to agree on how to respond to the disclosure regime, Government business manager Christopher Pyne said the Gallagher case would provide guidance on whether the three other MPs should quit Parliament. But the outcome of the Gallagher case may not be known until the High Court sits in February.

Targeting Mr Shorten, who had for months insisted his party’s processes were watertight, Mr Turnbull said that the Opposition Leader had been running a “protection racket”.

“Bill Shorten, despite saying there were no problems on the Labor side and everyone was fine, their checking was perfect, we now have a number of them that were dual citizens,” Mr Turnbull said.

“Why didn’t he tell us about that before?”