John Banks says he kept political donor Kim Dotcom briefed on the progress of his application to buy 45 hectares of Kiwi land for $45 million.
The statement has been backed by Dotcom - but Mr Banks' "good friend", Land Information Minister Maurice Williamson, denies any information came from him.
The apparent contradiction has been seized on by opposition parties who have called on the pair to disclose everything about their contact over Dotcom's bid to buy land.
The lobbying-for-land call by Mr Banks emerged after Dotcom said he had given $50,000 towards the politician's failed 2010 Supercity mayoral campaign.
Dotcom, who is facing an extradition process to the United States on charges of criminal copyright, said Mr Banks - then the Mayor of Auckland City - asked him to split the amount into two $25,000 cheques.
Mr Banks has maintained he knows nothing about money from Dotcom, but did lobby on his behalf over the property.
His efforts followed an application by Dotcom to the Overseas Investment Office - overseen by Mr Williamson - for permission to buy three properties.
Documents released under the Official Information Act show Dotcom wanted to buy the $30 million mansion he was renting in in Coatesville, its $5 million neighbouring "cottage" and a $10 million beach house at Doubtless Bay in Northland.
The application to buy the properties went to Mr Williamson, who gave formal approval on April 7 last year.
Dotcom's bodyguard, Wayne Tempero, said he took a call from Mr Banks about the application. The call was to let Dotcom know the application was going ahead as expected and that Mr Williamson had signed it.
Dotcom said Mr Tempero briefed him on the conversation.
Last night, Mr Banks confirmed he had updated Dotcom's staff about the application to buy the land.
A spokesman said: "Mr Banks communicated with Mr Tempero that the OIO application was continuing to progress through the approval process."
But a spokeswoman for Mr Williamson said he had given no information to anyone outside his office over giving approval to allow Dotcom to buy the land.
She later said the OIO often received inquiries about the progress of applications, but until decisions were made, the correct response was that the issue was going through due process.
Labour leader David Shearer said the apparent contradiction added to the lack of clarity over Mr Banks' behaviour.
"Somebody must have told John Banks - otherwise why would he go back to Dotcom and Tempero."
Mr Shearer said the lack of information could be easily resolved if Prime Minister John Key would speak to Mr Banks and ask what had happened.
New Zealand First leader Winston Peters said he was sure Mr Tempero and Mr Banks' recollection was accurate. The paperwork showed Mr Williamson had "signed it off".
He said Mr Key had dealt "flippantly" with questions over the issue.
"I think he thinks he can tough it out. He would be very unwise to think that."