The Morrison government awarded a $500,000 sports grant in the rural Victorian seat of Mallee a year and a half after it was first rejected – when the seat became hotly contested due to the resignation of Nationals MP Andrew Broad.

The Northern Grampians shire council applied for the grant in September 2018 and was rejected in the first round of the controversial community sport infrastructure grant program, only to see the $500,000 Lord Nelson Park project in St Arnaud approved in April 2019, just weeks out from the election.

Bridget McKenzie, the deputy Nationals leader and former sports minister responsible for the $100m program’s distributional bias in favour of marginal seats, has so far resisted mounting calls to step aside or face a Senate inquiry into the program.

In a scathing report, the auditor general found that 70% of projects announced in the second round in March 2019 were not recommended by Sport Australia, rising to 73% in the third round in April 2019 after an extra $40m was tipped into the program.

A further Guardian analysis shows at least 69 of the 228 projects approved in the project’s third round – when the election campaign was well underway – were in marginal seats. In Western Australia and Queensland, more than 80% of the projects approved in the program’s third round were in Liberal and National seats.

The analysis also shows how money began to flow to seats like Mallee deep into the election campaign.

Mallee, a safe National seat, was thrust into the national limelight in December 2018 when Broad quit after allegations about improper conduct on a work trip.

The seat attracted two Coalition candidates and a large field of independents, before the National candidate, Anne Webster, comfortably won the seat despite a large primary vote swing against her.

Analysis of data on the Sport Australia website shows Mallee received $1.47m in grants but only $67,886 was awarded in the first round of the program. The vast majority ($1.4m) of the money was given in the program’s final two rounds, including the $500,000 Lord Nelson Park project in round three.

A former councillor and mayor of Yarriambiack shire council, Ray Kingston, who ran in the seat of Mallee as an independent, told Guardian Australia that it was “more than suspicious” that the electorate experienced a “massive, unprecedented spike of announcements” in the lead-up to the 2019 election, including through the sports grants program.

A spokesperson for the Northern Grampians shire council confirmed the Lord Nelson Park project for a “multipurpose community sporting and events precinct” to encourage participation by women, girls and the elderly was unsuccessful in the first round but later funded in the third round.

According to the council’s website, the Lord Nelson Park grant was announced by McKenzie and Webster on 4 May, a fortnight before the election.

Kingston said “given what’s come out” about the way McKenzie’s office ran a parallel selection process, he believed, it was “just about a certainty” the grant was targeted at the seat because it was hotly contested.

“I ran specifically because I believe Mallee has been missing out for years and years,” he said. “Now we see the political pressure here bearing fruit.”

Webster has defended Mallee’s share of sports grants, which she said amounted to 4.8% of funding allocated in Victoria.

“In a sense we’ve received more than our population base compared to the rest of Victoria just slightly, so I think you’d be pushing [it] to say that we were pork-barrelled in any way,” Webster reportedly told the ABC. “I think the sport grants opened in the latter part of 2018 and it just so happened that I was preselected in the January, so the decisions of the sports grants were made in the March and the April.”

On Friday, Anthony Albanese said that McKenzie’s position was untenable because Sport Australia’s recommendations had been “ignored in favour of political decisions … based upon the marginality of electorates”.

Fergus Chisholm, the secretary of the Woodend tennis club in the safe Labor seat of Bendigo, told Guardian Australia its application for a joint facility with Braemar College was rejected after about 20 hours of work and “a few thousand dollars for consultants’ reports”.

Chisholm said revelations the funding allocation was skewed were “very disappointing” but the club was “fairly philosophical” about whether it had missed out as a result.

“We’re not particularly aggrieved – you don’t always get every grant … I’d prefer not to buy into that.”

On Friday, the Greens, One Nation and Centre Alliance all lent support to a Senate inquiry of some form. Labor has vowed to force the government to reveal the list of recommended projects overturned by McKenzie.