An Auckland man is fighting to find out how his home came to be onsold for a $45,000 profit within days of him selling it.

Ram Rai sold his three-bedroom home for $555,000 in March last year through ReMax Pinnacle in Royal Oak.

He then discovered on the day of the sale that a third person was paying $45,000 more through another agent in the same office to buy it off the first purchaser.

The house had a CV of $630,000 and had had a recent valuation of $780,000 but had been passed in at auction.

Rai complained to police and the Real Estate Agents Authority about the sequence of events leading to the sale and alleged the agency had improperly taken two commissions from the same transaction.

However, police said they were powerless to act and the authority's complaints assessment committee has recently cleared the two agents. It said there was not "sufficient evidence to uphold a complaint of unsatisfactory conduct". It found the sales process fair.

The dispute began when Rai received a conditional offer from Rajendra Prakash for his house in Lynfield. It contained a 72-hour cash-out clause, giving the seller the ability to cancel the contract for a cash offer - unless the buyer could come up with the money in three days to ward off the higher bidder.

When another buyer lodged a higher, unconditional offer, the cashout was invoked and Prakash came up with the $555,000. He quickly sold it for $600,000 to Chester Sherab, who lodged the second offer that Rai had been keen to take. Rai said he only found out about the subsequent sale from his lawyer and said he believed agent Lynlie Walsh should have told him it was being resold. "Prakash sold it back-to-back before he'd even paid the deposit."

He said Walsh and ReMax netted a commission of almost $18,000 from him and he presumed the second sale brought another, higher commission as the price was higher.

Rai wrote a letter of complaint to ReMax Pinnacle director Ashok Patel, who apologised and offered a $10,000 discount (almost 60 per cent) on the agent's commission. But he denied deliberate wrongdoing. "Although we don't approve of the situation that occurred, we do not believe that there is any intention on the part of our salespeople to mislead you or your wife," Patel wrote.

The authority agreed, putting the agents in the clear. Patel said: "It's just a no-brainer. It's been thrown out of the REAA. We have not done anything unfair, we are the victim in all of this, we have been hassled and hassled."

Rai has not been able to ask the man who resold the property how the second sale came about - he hasn't been able to track Prakash. A private investigator hired by Rai failed to find him.

But the man now living in the home, Sherab, insisted the second sale was above board.

"We were feeling disillusioned when the call came in to say we missed out on the house, so I wondered whether we should make a better offer," he said. "So we made the offer through Walsh and she said she would ask their agent to put it to them [the new owners]."

Sherab, who had been looking for a home for more than a year, said he believed it was not unusual for houses to be resold this quickly.

The authority said that since the deal with Prakash had gone unconditional, it was appropriate for a new offer to go to him.

Rai tried to fight his case in the Auckland District Court but had to stop after racking up $50,000 in legal fees.

He said he was now taking the fight to the Real Estate Agents Disciplinary Tribunal through an appeal.