Reports say deputy PM Michael McCormack billed taxpayers for Melbourne Cup flights and justified them by re-announcing an old election promise.

Deputy prime minister Michael McCormack and his wife flew to Melbourne on a VIP government jet before the Melbourne Cup last year and celebrated the race in Tabcorp’s marquee alongside other ministers, gambling executives, and Australia’s richest woman, billionaire Gina Rinehart.

He flew to Melbourne on an RAAF special purpose jet on a Sunday, made a funding announcement on Monday, attended the race on Tuesday, and flew out at public expense on Wednesday.

He flew to Melbourne for the official purpose of announcing $4 million in federal funding for a proposed indoor sports facility being built by Stonnington City Council in south-eastern Melbourne.

That same funding was announced by former member for Higgins, Kelly O’Dwyer, three years earlier, but has been mired in legal proceedings in the Victorian supreme court ever since.

Local councillors were reportedly shocked when they found out an event had been organised to “promote the federal government’s grant of $4m”.

“This is quite extraordinary: what is the real purpose of this media event?” one councillor, Sally Davis, asked the council’s chief executive, according to internal emails obtained by reporters.

“Kelly O’Dwyer announced/promoted this $4m election promise three years ago; so what is the rationale behind this repeat announcement? Whose idea was it?”

Local councillor Glen Atwell told reporters this week that: “Many residents were surprised to see the deputy prime minister in inner-city Prahran reannouncing a council project planned for Malvern East, at the opposite end of the municipality”.

“This project has been announced more often than the mythical high-speed rail. Bang for buck doesn’t even begin to describe it.”

On the Friday before the Melbourne Cup, a Nationals party room meeting was held in Nagambie, just over an hour north of Melbourne.

Backbencher Llew O’Brien says Mr McCormack organised the party room meeting so that MPs could legitimately claim travel expenses to attend the Melbourne Cup.

“It was only after my protests that the people going there paid part of their own way,” he told the Australian.

“And I would say that a response from certain party [MPs] in relation to that was quite negative towards me, and inappropriate.”

The Independent Parliamentary Expenses Authority told the Australian at the time that “any member staying in Melbourne for the weekend could neither claim the cost of their return travel on Sunday, nor any travelling allowance. This advice was provided to Nationals MPs ahead of time.”

Mr McCormack reportedly left that Nationals’ party room meeting on Friday, drove roughly three-and-a-half hours back home to Wagga Wagga in NSW, and then took the RAAF special-purpose jet to Melbourne on the Sunday before the Melbourne Cup, while he was acting as prime minister.

The current rules for travel expenses state that MPs must be travelling for the dominant purpose of parliamentary business. It is expected that re-announcing an old, legally stymied project would constitute parliamentary business.

A spokesperson for Mr McCormack said this week that “the deputy prime minister travels in accordance with the guidelines set by the Independent Parliamentary Expenses Authority (IPEA)”.