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AN email at the centre of the OzCar affair has reportedly been found and appears to have been concocted inside the Treasury Department.

Australian Federal Police (AFP) believe the email was sent from Treasury to the home account of Treasury official Godwin Grech, the ABC reported.

Federal police had executed a search warrant at Mr Grech's Calwell house and were now interviewing Mr Grech about the email, it said.

The AFP would not confirm whether they had searched the Canberra home of Mr Grech.

"We will commence talking to officials as soon as possible," an AFP spokesman told AAP.

Mr Grech's evidence to a Senate inquiry last week appeared to contradict statements Prime Minister Kevin Rudd and Treasurer Wayne Swan made to parliament about special treatment the government provided to Queensland car dealer John Grant.

Mr Grech told the inquiry on Friday that his recollection was that a staffer of the prime minister sent him an email about Mr Grant, but that he did not have the email anymore.

He also told the inquiry that Treasury officials gave him the impression that Mr Grant "wasn't your average constituent".