Vanuatu's opposition leader, Sato Kilman, says he will pay a courtesy call on the Prime Minister and to request him to resign.
Radio Vanuatu reports Mr Kilman as saying that after a series of defections, the Prime Minister Edward Natapei is now heading a minority government.
This comes after several government MPs reportedly swapped sides when the Speaker, George Wells, was dismissed from the National United Party for alleging that a minister, James Bule, had misused hundreds of thousands of dollars in subsidies.
On Monday, the opposition announced it had lodged a motion of no confidence in Mr Natapei's government.
There have also been reports that some opposition MPs have switched sides to join the government.
A spokesman from the Office of the Prime Minister says the government is working to rebuild its numbers, but is willing to step down and allow for an alternative administration if this Thursday's meeting proves they lack numbers.