The land was one of eight properties seized by the bank so they could be sold to repay his $20.5 million outstanding loan.
Mr Hart, who was struck off last year after being found guilty of three misconduct charges by the Lawyers and Conveyancers Disciplinary Tribunal, fought being ordered out of his home on State Highway 16, but his bids were not successful.
An ANZ spokesman said when Mr and Mrs Hart left, they removed sheep, cattle and dogs but left behind about 15 horses.
Mr Hart would not tell the bank who owned the horses but eventually he removed about five of them.
The spokesman said ANZ had no legal right to sell them under their mortgage.
"We were concerned about the welfare of the horses if they were left unattended. We wanted to make sure the horses were okay, so we had them examined by a vet who confirmed that they were healthy.
"While it wasn't technically our responsibility to look after them, we transferred them to the council pound at Pakiri where they could be properly cared for," the spokesman said.
Auckland Horse Havan owner Debbie Barker, who went to the auction, received calls from people worried about the horses. She said she was deeply concerned about two of the older males who were emaciated and in a very poor condition.
"It was really upsetting, to be honest."
Mrs Barker said the other horses were "okay" but needed to gain a little bit of weight. She bought one of the mares for $120.
She said all the horses looked to have gone to "really nice" homes.
An Auckland Council spokesman said the horses were impounded by the mortgagee because they were deemed to be trespassing.
The council issued a notice to the person believed to be the horses' owner. It also fed and cared for the horses until they were put up for auction on Tuesday and kept money from the sale to cover costs.
The horses could have been claimed up until the moment they were sold.
The council has not been able to confirm ownership of the 10th horse which will be sold at auction on July 18 unless it is claimed beforehand.
Mr Hart's lawyer, Jeremy Bioletti, said when ANZ took over the property all the horses were in good condition.
The bank put 24/7 security at the gate so "there was no way anyone could get back on to the property".
Mr Bioletti said he did not know whether Mr Hart made any attempt to claim the remaining horses or to make arrangements to have them cared for.
He refused to clarify the point with Mr Hart.
What they sold for
* 1 Bay mare, 15hh - $100
* 1 Bay mare, 15.1hh - $25
* 1 Dark bay mare, 14.2hh - $310
* 1 Light bay mare, 15.2hh - $120
* 1 Dark bay mare, 15.1hh - $100
* 1 Bay mare horse 14.2hh - $120
* 1 Irish hunter cross mare - $1050
* 1 Chestnut gelding - $210
* 1 Bay gelding, swelling on right knee - $210
* Figures excluding GST.
