Frontbencher David Littleproud joined in the defence of Senator Bridget McKenzie's controversial handling of $100 million in sports grants on Tuesday, saying she is "doing a damn good job".

His backing of his Nationals colleague came as it emerged that hundreds of thousands of dollars in grants went to wealthy tennis and golf clubs, while poorer clubs missed out.

Mr Littleproud said he was confident the program was rolled out according to guidelines, and Senator McKenzie had his full support – despite a scathing auditor-general's report suggesting money went overwhelmingly to marginal and in-doubt Coalition seats ahead of the May 2019 federal election.

"She's doing a damn good job," Mr Littleproud said on Tuesday.

"Now as agriculture minister, moving on from sport into agriculture, she's doing a damn good job in making sure not only do we continue to grow agriculture but help our agriculture adjust through these tougher times."

According to a report in the The Guardian on Tuesday, Perth's Applecross Tennis Club was given $500,000 to upgrade courts. The club is in a safe Liberal seat, and its patron is a Western Australian Liberal MP.

"Located on The Strand in Applecross, Perth, Western Australia, right on the Swan River foreshore, we have million-dollar views of the river and city, 12 grass and two synthetic hard courts," the club's website says.

Other grants went to the Tea Tree Gully Golf Club, in the Adelaide Hills. It received $190,000 for a new foyer and lift as part of an upgrade to attract more functions.

Royal Adelaide Golf Club – which had $5.3 million in revenue in 2019 – was given $50,000 for solar panels.

Club general manger Andrew Gay told The Guardian the money saved as a result would be used to help boost community participation.

“The funds we saved on this installation are being directed towards our junior and female development programs,” he said.

“These programs are open to the community if they wish to learn how to play the game.”

South Australian independent Rebekha Sharkie was excluded from sports funding announcements as the Coalition targeted her seat of Mayo in the 2019 election.

"I was a little disappointed that it was prior to the election and I wasn't included in any announcement," she said on Tuesday, standing alongside Mr Littleproud.

"I'd like to think that the local federal member can always be included when it's outside of an election period."

'Sports rorts' minister Bridget McKenzie doing 'damn fine job'_1
Inset: Liberal candidate for Mayo Georgina Downer handed a grant to the Yankalilla Bowling Club in February. Photo: Facebook/Georgina Downer

Ms Sharkie's Centre Alliance party will support a Senate inquiry into the so-called "sports rorts" affair.

Meanwhile, an eminent legal expert has suggested the controversial program might be unconstitutional.

Professor Anne Twomey said there appeared to be no basis for the scheme and questioned whether Senator McKenzie had breached the constitution.

"What is astonishing about the latest sports-rorts affair is its brazenness, culminating in the assertion that 'no rules were broken'," Professor Twomey, a professor of constitutional law at the University of Sydney, said in the Australian Financial Review.

Professor Twomey believes the legal obligation on ministers to behave in a procedurally fair manner, Senator McKenzie's legal ability to make the decisions, and whether or not she breached the constitution are all in question.

Senior Nationals MP Darren Chester welcomed the fact the scheme was now under review.

"The integrity of the way we deliver these types of programs needs to have the transparency that people can have confidence that a fair system is in place," he told ABC News.

"There have been great deliveries under this program. The question is whether the decisions were based upon merit."

Senator McKenzie has refused to apologise and Prime Minister Scott Morrison is standing by his embattled colleague.

“This was about ensuring the girls didn’t have to change behind the sheds, they could actually have a changing room in the shed,” Mr Morrison said on Monday.

Labor's former sports minister Ros Kelly stepped down from the ministry and then parliament in 1995 following a similar scandal.

-with AAP