Green MP Keith Locke says that any changes to the royal succession laws must end all discrimination against Catholics.
British Prime Minister David Cameron has proposed to other nations with Queen Elizabeth as Head of State a change in royal succession law to remove the bias against female heirs and the disqualification on a heir who marries a Catholic. The move, which Mr Cameron is pushing at CHOGM, would require legislative changes in several Parliaments, including New Zealand's.
"The Government should tell Mr Cameron that any reform bill going through our Parliament will also end the prohibition against a Catholic ascending to the throne," said Mr Locke.
"To do otherwise makes a mockery of our Human Rights Act, which prevents discrimination on religious grounds.
"We should ask Mr Cameron to be a little bolder and remove all discrimination against Catholics.
"If that means the Monarch can no longer automatically be head of the British Anglican Church, so be it.
"Of course, all these changes leave more fundamental questions like why our Head of State lives in Britain and why the Head of State is determined by inheritance, rather than by a democratic process.
"We only need to look to Ireland for a good example. The Irish go to the polls today to elect a non-executive president who has limited powers, not dissimilar to those of the British monarch," said Mr Locke