The source alleged those attending the auction were told by the organiser not to on-sell the items through channels such as TradeMe.
The council's acting chief executive, John O'Shaughnessy, confirmed an auction to dispose of surplus plant and equipment used by the council's parks and reserves division was held on April 1.
Mr O'Shaughnessy said the auction was advertised internally and was attended by staff members of the Maintenance Group, a business unit of the council, whose role includes maintaining the district's parks and reserves.
Hastings District Council has a "disposal policy" setting out its practices and procedures for the sale of surplus plant and equipment.
The policy states council-owned assets should be disposed of in an "impartial manner" and "to the best advantage of council as a whole".
Hawke's Bay Today asked the council if it was satisfied the disposal policy had been followed at the time of the auction.
"It is uncertain at this stage whether council policy has been fully followed and as a consequence I have begun an internal investigation," Mr O'Shaughnessy, said.
Asked what action had been taken in relation to any identified breach of the council's policies, Mr O'Shaughnessy said the investigation was proceeding.
"If any issues arise where staff have not followed policy to the expected standard, I will deal with them through the normal employment processes," he said.
Hastings Mayor Lawrence Yule said his understanding was policies may not have been breached although those policies were "loose" in relation to the particular matter being investigated, and the issue was complicated by the issue of whether the business unit's or overall council's policies should apply.
Mr Yule said he could not comment on Mr O'Shaughnessy's ongoing investigation or the action that would result from it.
"But no matter how you look at it, I don't think it is right that the council conducts auctions of its own gear and I don't think that will happen in the future," he said.
The total value of the items involved was believed to be less than $5000.
"It's a small amount of money, it shouldn't have happened and the officers know about that now and that's pretty much the end of it," Mr Yule said.
"It's probably a slight lack of judgment by some staff members who are good staff members but need to think about how they do things and the public perception of [their actions]."