Labour leader Helen Clark gave a strong ticking-off to party president Bob Harvey yesterday over his claim that the CIA was involved in the death of former Prime Minister Norman Kirk.

The claim was dismissed as "a heap of crap" by former Labour deputy leader Bob Tizard, and as "bizarre and sad" by Prime Minister Jenny Shipley.

Helen Clark comprehensively distanced herself from Mr Harvey over the claim, saying she believed there was no substance to it whatsoever.

She said she hoped to meet United States President Bill Clinton during the Apec meeting in Auckland but would not act on Mr Harvey's suggestion that Mr Clinton be asked to release CIA files on Mr Kirk.

United States Ambassador Josiah Beeman said that Mr Harvey "has been reading too many Nicky Hager spy novels."

"Next thing we know he will be blaming the CIA for the All Blacks losing to Australia last Saturday."

Last night Mr Harvey was unrepentant and said he would not back away from his claims. He said Helen Clark had told him his comments were "not the most helpful things."

"Helen Clark probably has every right to be dismissive, but it has nothing to do with her either. She was still at school ...

"It's an historic thing which is part of my culture and my past."

Mr Harvey said he had made no secret about his long-held suspicions and unanswered questions surrounding Mr Kirk's death in 1974.

"I think that Shipley - and I'm serious about this - should ask Clinton when he turns up at Apec, 'Did the American Central Intelligence Agency have a role to play in the removal of ... the Kirk Administration?'

"The answer is yes."

He said the circumstances of Mr Kirk's death were mysterious and had not been properly investigated. He believed Mr Kirk was poisoned on an overseas trip.

Helen Clark described the claims as conspiracy theories and a trip down memory lane.

The rumours had long been circulating and had no substance.

"I have conveyed my strong view on this to Mr Harvey," she said.

Mr Tizard told National Radio that Mr Kirk had been diagnosed in 1941 as having an enlarged heart.

Mr Kirk was excessively overweight, at times weighing up to 172kg.

Before entering Parliament in 1957 he kept fit by doing manual jobs but after becoming an MP he ignored medical advice to cut down on his eating.

Mr Kirk died of a heart attack 25 years ago yesterday.