The former Niue cabinet minister, Togio Sioneholo, says the government is acting unconstitutionally in appointing MPs as assistant ministers.
Mr Sioneholo, who is a former secretary of justice, says that under the constitution Niue is only allowed to have four ministers.
He says creating two so-called assistant ministers is a devious way to circumvent the constitution.
Mr Sioneholo is asking the Niue High Court to declare the government's actions unconstitutional and have the assistant ministers repay the extra salary they've been paid.
"The matter should have been taken out to the citizens of the country to determine whether we need to amend the constitution and provided for a number of other ministers or another category of ministers assisting or whatever, but that's the proper procedure, not come round through the back door and start playing with words - they're not ministers, just a minister assisting a minister or something."
Togio Sioneholo, who's also taking legal action over the swearing in of an MP in Auckland, which he says is also unconstitutional.