No confidence votes have become a frequent feature of PNG politics.
But parliament has passed a constitutional amendment extending the grace period protecting a newly elected prime minister from such a vote from 18 to 30 months.
The amendment passed through parliament with the support of 90 MPs; only 14 voted against it.
The Prime Minister, Peter O'Neill, says it will improve political stability and allow the government to focus on delivering services and implementing policies rather than the constant fight for survival.
The Opposition says stability is earned, not legislated and the amendment will entrench bad governments.