The Vanuatu opposition leader Ishmael Kalsakau has not ruled out filing a motion of no confidence against the government when parliament sits next Friday.
The loss of the Leaders Party's eight MPs on Wednesday means the government of Prime Minister Charlot Salwai only has a one seat majority.
Mr Kalsakau would not be drawn on how many MPs now support him, saying he is more interested in building a perfect team.
He said he could either develop a strong opposition which will support him until the election in January 2020, or push for a vote of no confidence.
"There are two options available to me at the moment. One is to either develop a destructive and perfect opposition to last me until the elections, and you'll be expecting a lot of fireworks in parliament in 2020," he said.
"The other consideration is if there is such a need to - because of the poor performance of the government - to effect change, to take over the leadership, to provide much needed service delivery to the people."
"If it appears that there is a further change in mindsets or numbers, then I certainly would proceed to file a motion of no confidence. There is a lot of occurrences in government at the moment that are seriously questionable," Mr Kalsakau said.