John Key

Wellington, May 17 NZPA - Prime Minister John Key says he is not concerned a box containing live flies a label "this is a New Zealand cluster bomb" made it to a Cabinet minister's office on the fifth floor of the Beehive earlier today.

The whole executive wing was evacuated when the package was discovered about 8am by an arriving worker in Agriculture Minister David Carter's office.

Staff were told just after 10.30am they could return to the building.

Mr Key said the package was wrapped in brown paper and he would have been more concerned if it had been labelled as a bomb on the outside.

"I'm advised it went through the appropriate screening requirements as it came into the building and nothing at that point detected. It was at the point it was unwrapped in the minister's office that the words 'this is a New Zealand cluster bomb' were unveiled.

"It had flies in it apparently...it didn't come with a can of Black Flag that's for sure," Mr Key told reporters.

Wellington police district communications manager Elizabeth Young said the package was taken by police for forensic examination.

Wellington CIB staff were also investigating how the item was delivered to Parliament.

Anyone with information was asked to contact police.