The case concerning Mr Mailley dates to 2008 when he faced extradition to Australia, for what he says were "attempted fraud charges".
Mr Mailley said he took Mr Hart on because he had a reputation as a "rock star" lawyer.
Correspondence from Mr Hart to the Law Society shows Mr Mailley was billed more than $310,000, which included charges for phone calls, prison visits and case preparation.
The bill shows the barrister charged $1000 an hour, although some of the work was carried out by less experienced lawyers and charged at a lower rate.
Mr Mailley said he and his wife paid more than $200,000 in legal fees. He said he lodged a complaint with the Law Society about Mr Hart's fees in February 2009.
Documents from the Law Society show its Auckland Standards Committee intended to investigate the complaint of "overcharging of fees" and an allegation Mr Hart had failed to give Mr Mailley information about his fee structure. The Law Society would not comment.
However a senior QC with more than 30 years' experience in criminal law was called in to work on the issue, but the hearing did not happen.
Mr Mailley said that was because his new lawyer, Graeme Minchin, drew up a confidential repayment deal, which has been seen by APNZ.
It states that if Mr Mailley withdrew his complaint to the Law Society, Mr Hart would deposit $150,000 into his bank account.
Mr Mailley said he told the Law Society he wanted to withdraw his complaint but says he is waiting for Mr Hart to repay most of the $150,000.
Mr Hart did not return phone calls and was not at his legal chambers in Auckland when APNZ visited.
Mr Mailley said he was confident he would get his money back and is planning further legal action.APNZ
