A Tongan MP Sitiveni Halapua says he was dropped from the Democratic Party because he wanted it to work together with other MPs.
Last month, Dr Halapua and three colleagues were removed from the party's roster of candidates for the November election.
Another two MPs sided with the dumped group last week.
The party leader, Akilisi Pohiva, has claimed a conflicting doctrine prompted the MPs' removal, but Dr Halapua says that is not correct.
He says Mr Pohiva was opposed to his push for the Democrats to work more closely with other MPs in the Legislative Assembly.
"The idea of one party - win and get the majority and run everything - I think it is an old fashioned way of thinking. The world has changed and I have seen that in New Zealand, in Australia and in other Commonwealth countries where it is important for people to think about forming coalitions."
Tongan MP Sitiveni Halapua