Six of them are from the Reunification of Movements for Change (RMC), including Christophe Emelee, who was the deputy leader of the opposition until yesterday.
The president of RMC and former Prime Minister Charlot Salwai said the MPs were approached by the government to join them.
The defection means the Bob-Loughman-led coalition government now commands 37 MPs, out of 52.
The government now has a comfortable number of seats to pass the 2022 budget in this session, which requires a two-thirds vote.
The opposition is now reduced to 14 MPs.
