Regional Pacific leaders are refusing to comment about the Marshall Islands lawsuit filed against the nine nuclear powers.
The Marshall Islands says the nine powers are failing their obligations to disarm as stipulated in the Non-Proliferation Treaty.
The Pacific Islands Forum, which pushed for the ban of nuclear weapons from the region, has declined to say whether it supports the Marshalls case in the International Court of Justice.
The US is being sued in a US federal court because Washington refuses to recognise the ICJ.
While New Zealand's opposition Labour Party's disarmament spokesperson, Maryan Street, said she would be asking the foreign minister to support the suits, Murray McCully responded to say he did not wish to make any comment.
In the 1970s New Zealand took France to the ICJ in an attempt to halt the testing of nuclear weapons in the South Pacific.
The US and Russia say they have sharply reduced their stockpile of atomic weapons.
The foreign ministry in Israel, which has not signed the treaty, has been quoted as saying the ICJ case against countries outside it does not have any legal legs.
The International Atomic Energy Association, which was set up by the UN to inspect nuclear activities around the world, says it will not comment on the legal dispute.