A French Polynesian opposition assembly member has joined the group led by the president, Edouard Fritch, which gives him a majority
Joelle Frebault says her decision to leave the pro-independence Union For Democracy reflects her electorate's wish to have stable government.
Her defection gives Mr Fritch the backing of 29 MPs in the 57-member assembly.
His Tapura Huiraatira group also has the support of the Atia Porinetia Party which decided to back Mr Fritch after rifts deepened within the once dominant Tahoeraa Huiraatira Party last year.
The split occurred after the Tahoeraa leader, Gaston Flosse, lost office over a corruption conviction, prompting his replacement by his deputy, Mr Fritch.
The change was followed by resignations and expulsions, reducing the Tahoeraa's numbers in the assembly to less than half of its post-election figure.
Mr Fritch, who is yet to form a proper party, warned two months ago that if he failed to pass the budget he would consider his work done.
There has been no government reaction to today's announcement by Mrs Frebault.