The secretary general of Vanuatu's National United Party, Willie Jimmy, says they have brought stability to the country by joining the Government coalition.
The NUP's 11 MPs agreed to join on Wednesday with Mr Jimmy becoming Public Utilities Minister and the NUP leader, Ham Lini, is the new Deputy Prime Minister.
Mr Jimmy says they joined after the government backed their candidate for President, Kalkot Mataskelekele.
A vote of no confidence in the Government, which the NUP had helped promote while in Opposition, is likely to be heard next week following a Supreme Court ruling yesterday.
But Mr Jimmy says it will fail now the NUP has changed sides.
"Now that the National United Party is part of the Government and though the Supreme Court is ordering the Speaker to call for an extra-ordinary session, that motion will be defeated anyway because we will not support that motion."