Key: Top leaders welcome to speak in House

Gillard's address in chamber will be outside Parliament's hours because Greens objected. Photo / Getty Images

US President Barack Obama, British Prime Minister David Cameron or German Chancellor Angela Merkel would likely be invited to speak in Parliament if they visited New Zealand, Prime Minister John Key indicated yesterday.

Australian Prime Minister Julia Gillard, who arrives in Auckland this morning, will tomorrow be the first foreign leader to speak in the New Zealand Parliament - though not while the House is in session.

The Green Party objected to allowing a foreign leader to speak during a sitting of the House, saying it could undermine the democratic sovereignty of Parliament.

Mr Key acknowledged the Greens' objection but said at his post-Cabinet press conference: "It is something we would be very judicious about and careful with."

He was not going to invite every visiting leader to speak in the chamber, he said, "but clearly if the Prime Minister of Britain, or the President of the United States of America or a senior European leader came to New Zealand, we would consider that on a case-by-case basis".

Mr Key omitted to mention China, NZ's second largest trading partner after Australia. His office said the list was just illustrative.

The PM said of the timing of the speech: "We didn't want to have an embarrassing situation where the Prime Minister of Australia - giving her first formal address in our Parliament and the first foreign leader to do so - had some member of Parliament get up and object. On that basis we came to a compromise that she would speak outside of the normal sitting hours."

In Auckland, Ms Gillard will speak at a business lunch where she is expected to concentrate on the progress of work towards a single economic market - the synchronisation of policy aimed at making it easier to do business in each other's country.

Ms Gillard, a former Education Minister, will then visit Glen Taylor School in Glendowie - a political choice given that that was where Mr Key launched details of the controversial national standards for primary schools in 2009.

The two leaders will sign an investment protocol under the Closer Economic Relationship that will increase the threshold at which Australian investment in New Zealand business needs Overseas Investment Office approval from $100 million to $477 million and investment by New Zealand in Australian business from about A$230 million ($305 million) to just over A$1 billion.