Prime Minister John Key and seven cabinet ministers leave for Melbourne this evening for two days of talks with their Australian counterparts.
It's the second time Australian and New Zealand prime ministers have convened a joint meeting of senior ministers. The first was in 2009.
"The opportunity for two prime ministers and seven cabinet ministers on each side of the Tasman to share ideas on the challenges we face is extremely valuable and, of course, Australia is our most important relationship," Mr Key said.
"The willingness on both sides to make this happen reflects how important that relationship is."
Mr Key will hold bilateral talks with Ms Gillard and take part in the joint meetings.
Broad topics have been agreed, including the future of the relationship and the challenges both countries face.
Mr Key is also expected to raise the issue of Australia's 2001 law change which reclassified incoming Kiwis from permanent residents to temporary ones, cutting off their right to claim many social security benefits.
The Dominion Post last week reported Kiwi couple Glenda and David Campbell were suing the Queensland government because they've been denied disability services for their 19-year-old daughter who suffers from severe cerebral palsy.
A spokeswoman for Mr Key said he would discuss the situation with Ms Gillard.
Accompanying Mr Key are Finance Minister Bill English, Economic Development Minister Steven Joyce, Justice Minister Judith Collins, Health Minister Tony Ryall, Education Minister Hekia Parata, Defence Minister Jonathan Coleman and Commerce Minister Craig Foss.
NZN