In a letter to the Speaker of Parliament, the MPs have asked that their names not be considered part of any such motion brought before the house.
The MPs named in the letter are Hon. Christophe Hogtermon Emelee, Hon. Jack Wona, Hon. Tom Noam Iouniwan, Hon. Kalo Pakoasongi Lawo, Hon. Don Ken Stephen and Hon.Jack Norris Kalmet.
The four men, who have crossed the floor to join the government, said they believe their signatures had been forged from previous no confidence motions.
They urged the speaker to strike out any motion that is submitted bearing their names, and for an investigation to be launched.
Vanuatu's opposition leader has played down suggestions he may soon lodge a motion saying the opposition would only table one when it has the numbers to pass it.