The 2005 Budget has been passed by the Papua New Guinea parliament but the opposition leader, Peter O'Neill, says he intends to test it in court.
The National newspaper reports when the Bill was tabled, government MPs verbally aproved it, drowning protests from opposition members.
Mr O'Neill then gave notice that he would seek a court interpretation, saying that under the Organic Law, the matter should be decided by party resolution.
The government also did not allow all members the opportunity to debate the 1.5 billion US dollar budget which was presented on November the 16th.
After the speaker, Jeffrey Nape, advised that the budget had been passed, Mr O'Neill asked for clarification on the voting procedure.
He said there would be legal implications under the Organic Law.
Mr Nape replied that parliament had the power to pass the bill on voices.