The Papua New Guinea parliament is sitting this week and top of the agenda is again the plan by the opposition to try and remove Prime Minister James Marape.
A series of efforts by the opposition to bring a vote of no confidence so far this year have come to nothing and Marape said he has the numbers to avoid removal.
Last week, he said he was "relaxed" and "confident" at the possibility of being ousted.
The opposition is yet to name its alternate for the prime ministership.
Also last week, the opposition leader Douglas Tomuriesa essentially said the role was up for grabs, for anyone who thought they could do it, and had the backing.
RNZ Pacific's correspondent, Scott Waide, said the most significant move this week has been the defection of the Health Minister, Lino Tom, a senior member of the Marape/Rosso government.
He said he has raised a number of matters prompting his move, "including the state of the country in terms of law and order, the ability of police to control crime and the institutionalised corruption that he's seeing in state agencies".
"So it's a big, significant move."
Waide said Dr Tom appears to be looking at a whole of government approach and and a long-term perspective on the issues that he's mentioned.
"And there's a feeling that he joined the government because he thought that he'd be able to resolve those issues.
"As health minister, he's also been very frustrated by the budget cuts to the health sector, the difficulties in getting the medicines in on time because of budget shortfalls, that he's expressed time and time again in government."
Waide also said Dr Tom was critical of the provision of millions of dollars of funding by the Australian government for rugby league development in PNG, when that money could have been put to better use elsewhere.
Suspended MP, Bryan Kramer, who had been a cabinet minister, has also switched to the opposition benches.
He retains his seat due to a stay by the Supreme Court on a decision made by the Leadership Tribunal.
Waide said he doubts little else will be discussed in this sitting, so further delaying the tabling of the Bougainville independence referendum.