Crown Law says it did not tip off the National Party about a Serious Fraud Office investigation into New Zealand First.
The Serious Fraud Office on Thursday announced it is investigating donations made by Sir Robert Jones and the Vela family to New Zealand First.
A day before the SFO announced its investigation, National Party leader John Key ruled out New Zealand First as a possible coalition partner.
Prime Minister Helen Clark has suggested National may have known about the SFO's decision before its announcement, and says Crown Law and the police also knew.
The claim has been rejected by Mr Key and the SFO, which said on Monday it had received assurances from all staff involved in the New Zealand First donations matter that they have not leaked information.
A spokesperson for Crown Law says she can "absolutely" deny there was a leak from its office, while a police spokesperson referred all questions to the SFO.
Last week Mr Key ruled out New Zealand First as a possible coalition partner, raising suggestions National must have known that the investigation was coming.
However, Mr Key says that is wrong. He says the real question for Miss Clark is why it took her six months to reveal that expatriate businessman Owen Glenn had told her he had been approached by New Zealand First's leader Winston Peters for money.
That claim has been rejected by Mr Peters. Parliament's Privileges Committee is considering whether he should have declared the $100,000 donation from Mr Glenn.
