Two councillors who voted for projects worth hundreds of millions of dollars in Victoria's most populous and fastest-growing council area between them received more than $1.2 million in payments from a property developer and his associates, a corruption inquiry has heard.

Key points: The anti-corruption watchdog uncovered what appeared to be close financial ties between property developers, planning consultants and councillors, the inquiry heard

The anti-corruption watchdog uncovered what appeared to be close financial ties between property developers, planning consultants and councillors, the inquiry heard Public hearings are examining three projects which had come before the City of Casey in Melbourne's south-east

Public hearings are examining three projects which had come before the City of Casey in Melbourne's south-east One of the projects involved the attempted rezoning of industrial land for residential use

The Independent Broad-based Anti-corruption Commission (IBAC) has begun public hearings into allegations of corruption at the City of Casey, in Melbourne's south-east.

Forensic accountants for IBAC estimate personal payments to Councillor Sam Aziz and his related entities amounted to close to $900,000 and those to Councillor Geoff Ablett totalled more than $330,000.

The corruption watchdog launched Operation Sandon in August 2018.

Counsel assisting Michael Tovey QC told the inquiry IBAC had uncovered what appeared to be "very significant financial relationships" between property developers, planning consultants and councillors.

"There have been votes on matters … where councillors, who have been receiving money or other benefits from a developer, have failed to declare the receipt of such benefit," he said.

Mr Tovey said at times councillors failed to fully declare the extent or nature of the conflict of interest and tried to influence the vote of other councillors.

"The decisions which have been affected by these defective processes affect planning in respect of developments worth hundreds of millions of dollars," he said.

He said the hearings would focus on three projects in the City of Casey:

The Cranbourne West precinct structure plan

The Cranbourne West precinct structure plan Construction of an intersection in Hall Road at Cranbourne West

Construction of an intersection in Hall Road at Cranbourne West Development of the Pavilion housing estate

Developer's reach could extend to state politics

Mr Tovey told the hearing developer John Woodman maintained "a very close and controlling association with a core group of councillors".

"[They] were expected to and did line up votes in favour of his interests," he said.

The "corrupt" cash payments were structured in a bid to disguise the flow of funds from Mr Woodman and his related entities, Mr Tovey told the hearing.

Mr Tovey also claimed that Mr Woodman may have influenced state politics.

"His reach … is not limited to local council but appears to extend to state government over the last three elections," Mr Tovey said.

"He and organisations associated with him have contributed over $400,000 to state political campaigns."

The hearing was told John Woodman had a "controlling" association with a core group of Casey councillors. ( Watsons )

Mr Woodman, who is the director of Watsons Pty Ltd, is due to give evidence.

Watsons states on its website that it is responsible for "between 10 and 20 per cent of the total lots released to the Victorian market each year".

Councillor under scrutiny flew to Egypt

At the start of the hearing, IBAC commissioner Robert Redlich QC warned Mr Woodman he risked prosecution for perjury if he was caught lying in the witness box.

"So long as you give answers that are truthful, your answers cannot be used in any other jurisdiction against you," he said.

"They cannot be used in a court of law; they are not admissible."

Cr Aziz, a former mayor of Casey, will not be appearing at the inquiry as he is no longer in Australia.

Mr Tovey said Mr Aziz was earlier questioned in a private session and a few weeks ago flew to Egypt after selling his home.

"We are unaware as to if and when he might be returning," Mr Tovey said.

Mr Tovey said the commission had sought a restraining order over the proceeds of the sale of Cr Aziz's home.

Eleven witnesses are expected to give evidence over the next three weeks of hearings.

Former mayor argued against council officer advice

Mr Tovey said the Cranbourne West precinct involved the attempted rezoning of land set aside for industrial purposes for residential use.

"The rezoning of the land would have increased its value by well over $100 million," Mr Tovey said.

Cr Aziz was named as having a major role in promoting the proposal to council.

The City of Casey, which holds its council meetings at Bunjil Place in Narre Warren, is the most populous local government area in the state. ( ABC News: Dylan Anderson )

A final decision on the rezoning has not been made yet, Mr Tovey said.

Cr Aziz pushed for immediate construction of the Hall Road intersection, against the advice of the council's planning officers, the hearing was told.

This would have delivered "windfall profits" for the developer Wolfdene, for whom Mr Woodman was working as a consultant, by "enabling it to develop land well ahead of the time it otherwise would have been able to", Mr Tovey said.

Concern lobby group was 'creature of developers'

The Save Cranbourne West Residents Action Group (SCWRAG) also campaigned in support of the intersection.

Payments totalling $193,000 from Watsons and consultant Megan Schutz was deposited into an account associated with the president of the residents group.

IBAC is investigating whether SCWRAG was actually "the creature of developers."

Cr Aziz also successfully moved a development plan amendment to the Pavilion estate to reduce the amount of public open space and provide more land to be sold by Wolfdene.

The council's planning officers described it as a "poor outcome for residents" and users of the Casey Fields Regional Sports Complex.

Cr Aziz successfully argued to reduce the amount of public open space in the Pavilion development. ( liveatpavilion.com.au )

The City of Casey, in Melbourne's south-east, is Victoria's most populous local government area and one of the fastest growing in the nation.

It is home to more than 340,000 residents and includes the suburbs of Berwick, Narre Warren and Cranbourne.

In a statement, the City of Casey said it was fully cooperating with the investigation.

"We will work with the IBAC and implement the recommendations of the commission," it said.