Papua New Guinea's opposition now claims that as many as 30 MPs have sided with it as back room lobbying intensifies ahead of a no confidence vote next week.
Parliament sat on Friday for the tabling of an opposition motion of no confidence in Prime Minister Peter O'Neill, before being adjourned until next Friday when a vote will take place.
While there, Bire Kimisopa and his three New Generation Party MPs, as well as the government minister Ben Micah and his People's Progress Party, crossed the floor to join the opposition.
A spokesperson for the opposition said more MPs joined it on Saturday, and its members have entered a camp to plan and discuss their options ahead of Friday vote.
The leader, Don Polye, and his deputy, Sam Basil, were unable to be reached for comment on Saturday, but other MPs at the camp, who spoke on the condition of anonymity, said they were confident they would have the 56 MPs needed to topple the government by Friday.
But Mr O'Neill's government, which still commands a sizable majority, is also understood to be lobbying intensely.
Mr O'Neill and other government MPs could not be reached for comment on Saturday.
However, in a statement on Thursday, he said he was confident he would survive the motion, dismissing it as a costly attempt by the opposition to cause instability for the sake of political self-indulgence.
Meanwhile, air travel in Papua New Guinea was disrupted for a fourth day and workers at the nation's ports were deliberately working slowly as part of a protest against the Prime Minister.
A civil society said its stop work protest had disrupted air travel across the country since Wednesday as pilots of the state-owned airline, Air Niugini, chose not to fly.
The group wants Mr O'Neill to stand down to face fraud allegations that have dogged him for more than two years.
The PNG Maritime and Transport Workers unions said it advised its workers not to take part in the protest and that work at the ports was continuing normally.
But the civil society group's leader, the constitutional lawyer Moses Murray, said that while the port workers were not disrupting essential services, they were protesting peacefully at the same time.
"What would you interpret if you are unloading a container from a boat in two hours. It takes two hours to unload one container. They're working, but is their conscience fully with their work?," he said.