An uncomfortable John Key has confessed he should have told the public earlier about the full extent of his shareholding in rail company Tranz Rail and should never have held the stock for as long as he did after he entered Parliament.
The National leader made the admissions yesterday as he came under heavy fire from Labour at a time when he should have been launching attacks on his rival over the Winston Peters donation scandal.
With the election just over six weeks away, Mr Key is now the centre of a story which raises questions about how open he has been - just what Labour plans to push in the campaign.
"I should have acted to sell those shares earlier, that was a mistake," Mr Key said.
When he found out that his broker had bought 50,000 shares for his family trust in 2003 "I should have gone out then, in my opinion, and made that public information."
It has emerged that the National leader's family trust owned as many as 100,000 shares in Tranz Rail in 2003, a year in which he was sending in questions relating to the company to Finance Minister Michael Cullen.
Mr Key's trust already held some of the shares when he entered Parliament in 2002 but it bought some more in april 2003 while he was associate transport spokesman for National.
The shares and other New Zealand stocks the trust owned were sold in June 2003 after he told his broker to get out of the investments because of the risk of a conflict of interest.
Labour has attacked Mr Key for not declaring his interest and for saying just this week that he had owned 50,000 shares when it was 100,000.
"John Key lied because he knew he had something to hide," Dr Cullen said
Labour ramped up the pressure on the National leader in the house yesterday and Mr Key fiddled with his BlackBerry messager for a time before trying to laugh off the verbal attacks from across the chamber.
He has not been laughing about the issue in interviews, however, where he has appeared very uncomfortable. In an interview with TV One on Monday, where he said in response to a question that he owned 50,000 shares - only to correct it seconds later when challenged - Mr Key said he made a "genuine mistake."
He reject's Labour's suggestion he used his parliamentary position to make a gain. But it is the question of whether he has purposefully held back information that Labour is seizing on, and it will continue to do so for the duration of the election campaign.