Banks MP David Coleman's social media posts and past Leader articles call into question the federal government's defence of the $660m commuter car parks program.
The timing of the announcements shows Mr Coleman (Liberal) had already committed millions of dollars to local projects under the car parks program before the last election campaign had officially begun.
Federal government ministers have defended the scheme, described by Labor as "sports rorts on steroids", claiming the projects were election commitments.
Mr Coleman made the Hurstville and Panania car park promises in March 2019, but the federal election was not called until April 2019.
Recently, Finance Minister Simon Birmingham said the car park scheme was put to voters during the election, which meant "the Australian people had their chance" to judge it and had "voted the government back in".
A spokesperson for Urban Infrastructure Minister Paul Fletcher said all decisions regarding the Commuter Car Parks were made in the context of the Commonwealth's broader urban infrastructure investments.
"They were taken to the Australian people at the 2019 election," the spokesperson said.
A searing auditor-general's report found the commuter car parks program was not effective or merit-based and that many of the sites chosen were selected before the election campaign.
On March 27, 2019 David Coleman stood with the Prime Minister and said: "We've been able to secure $7.5m for a new car park in Hurstville."
Both announcements used the same language to describe the commitment, with no suggestion the project would not be delivered if the Coalition were not re-elected.
Prime Minister Scott Morrison said the investment would mean people in the St George area would be getting home sooner and safer. His language also suggesting the announcement was a budgeted commitment and not an election promise.
Budgets are usually handed down in May, but in 2019 it was brought forward to April 2.
The Prime Minister called the election on April 11, 2019, and the government went into caretaker mode.
Federal Labor member for Barton Linda Burney said the car park scheme was another in the long list of scandals engulfing the Morrison Liberal federal government.
"The ever-growing list of scandals surrounding the Morrison government shows why Australia needs a powerful and independent anti-corruption commission, which Labor has recommitted to this week," she said.
"Labor will also introduce a bill into the Senate to improve the transparency and accountability of ministerial decisions with grant programs.
"Two years later and only two of these car parks have actually been built nationally.
"St George has been struggling with congestion and lack of investment in transport infrastructure under the Liberals.
"The Liberals have gipped St George commuters and the government has serious questions to answer."
David Coleman did not address the Leader's questions directly, but he did issue a statement.
"Our area has some of the highest population densities in Sydney and lack of parking is a major issue," he said. "I have advocated for more parking in our area because our community needs it."