The new Vanuatu government says it needs the support of just one opposition MP for a two-thirds majority to change the constitution.
The coalition has 29 seats in the 52-member parliament, but also has the backing of five independents.
The prime minister, Edward Natapei, says development has been hampered by shortlived governments, with ten government changes in ten years .
He says to overcome this, the coalition will endeavour to change the constitution.
"We're looking at the perhaps putting in an amendment to ensure that members who cross the floor lose their seats as a result, and have to go back to face the election again .... a by-election."