The Papua New Guinea Prime Minister, Peter O'Neill, is seeking a Supreme Court interpretation on a recent planned vote of no confidence in him.
Mr O'Neill indicated at the weekend that he intends to resign this week, but on Monday he began the legal action which could delay that.
He claimed there was confusion around the constitutional process that led to the withdrawal of the opposition's motion last week.
In his application to the court, Mr O'Neill said that a no confidence motion was a serious constitutional process and that its withdrawal was unprecedented and disrespectful.
Mr O'Neill said his application was necessary to "prevent any legal motions that are an abuse of integrity laws and the Constitution".
A week ago the opposition said it had withdrawn the motion but had committed to lodging a new one, however the prime minister yesterday announced his intention to step down.
A spokesman for the prime minister said Mr O'Neill would visit the governor general to formally tender his resignation after the rules on votes of no confidence were clarified.