The lone opposition MP in the Cook islands, Norman George, is ruling out the possibility of working again with the prime minister, Dr Robert Woonton.
There have been reports that the current coalition, which is the fifth in less than four years, is shaky and won't last beyond the end of the week.
The leader of the Democratic party, Dr Terepai Maoate, has said he's not fully committed to the coalition set up Friday because he hasn't been given two cabinet posts as expected.
Mr George says Dr Maoate is in negotiations with him but he won't be returning to the current government.
"I have no desire whatever, to work with Dr Woonton again and neither will I ever have any desire to work with Sir Geoffrey Henry as well...because they are the ones that teamed up to sack me......And I was sacked for no other reason than political."
24 out of the 25 MPs are in the current coalition government.