A former City of Perth councillor spent thousands of dollars wining and dining family and friends for years at the expense of ratepayers, an inquiry has heard.

Key points: The inquiry follows a period of turmoil at the City of Perth, including the council's suspension

The inquiry follows a period of turmoil at the City of Perth, including the council's suspension Former councillor Keith Yong is the first public witness to appear before the inquiry

Former councillor Keith Yong is the first public witness to appear before the inquiry He testified councillors invited whomever they wanted to the Council House dining room

The inquiry, overseen by Perth Barrister Tony Power, is holding a series of public hearings as part of its investigation into operations and affairs at the City of Perth.

The probe was launched in April after a period of turmoil that included the gifts and expenses scandal surrounding Lord Mayor Lisa Scaffidi, infighting and accusations of bribery between councillors, two chief executive officers taking stress leave and the eventual suspension of the entire council.

Perth Lord Mayor Lisa Scaffidi was dismissed along with the rest of her council. ( AAP: Richard Wainwright )

Dozens of witnesses have already been interviewed in private as part of the inquiry, but the first public witness to appear was former councillor Keith Yong.

The Perth lawyer was elected in October 2013, and was a key backer of Ms Scaffidi before losing his position in the 2017 council elections.

He was today questioned about his use of the private dining room at Council House — the City of Perth's St Georges Terrace offices.

Elected councillors are eligible to use the plush private venue for official functions to the value of $12,000 each year.

The dining room situated on the top floor of the building in Perth's CBD. It has river views and councillors have full access to catering services, including alcohol.

Family guests invited purely for 'entertainment'

Mr Yong told the inquiry during his time on the council he dined with business leaders and consuls general at the venue.

The balance of power on the council has changed with Ms Green's election.

But he admitted he had also regularly invited friends and family to dine with him at ratepayers' expense, a practise that is forbidden under the council's policy.

The hearing was told that in the 2015–16 financial year, he racked up a $10,200 dining bill.

The following year he had more than 150 guests at a total cost of more than $11,600.

Mr Yong said the city had seen some return for that expenditure.

"It's part of the city's interaction and connection with stakeholders, which I think is important," he said.

But when he was asked what benefit had been derived from him entertaining family and friends at the dining room, he replied: "None."

"It was purely entertainment," he said.

"I did not have a careful look at the guidelines and policy."

'Unwritten rule' sees open guest invitation

Counsel assisting the commissioner, Philip Urquhart, asked Mr Yong what the point of such a policy was, if councillors ignored it.

"No point," he said.

He also conceded there was an "unwritten rule" among councillors that they could invite whoever they wanted to the dining room, particularly on Saturday nights.

Keith Yong regularly entertained family and friends at ratepayers' expense. ( ABC News: Charlotte Hamlyn )

It was found that over two years, Mr Yong had claimed a total of $56,000 in expenses including the use of the dining room, transport, education and travel costs.

During his time as a councillor he also billed ratepayers for a trip to the United States to attend a seminar.

He said that while his use of the dining room had not been ethical, all his other claims and actions as a councillor had been.

This round of hearings is focussing on five different areas:

elected members' entitlements

elected members' entitlements completion of primary and annual returns

completion of primary and annual returns the council's decision-making process regarding a particular application for planning approval

the council's decision-making process regarding a particular application for planning approval procurement and contracting of services, and

procurement and contracting of services, and whether criteria for voter eligibility is open to manipulation

Currently, companies who hold leases within the City of Perth can nominate two people to vote on their behalf.

But those people are not required to live within the city's boundaries or have any connection to the company they are representing.

Witnesses warned not to be swayed by 'misguided loyalty'

Philip Urquhart has been frustrated by the answers given by some witnesses in private hearings. ( ABC News: Charlotte Hamlyn )

Mr Urquhart today expressed some frustration at the progress of the inquiry so far, saying that during more than 70 days of private hearings, witnesses' answers had often lacked veracity and defied logic.

He issued a warning to future witnesses to abide by their oath to tell the whole truth and not be influenced by "misguided loyalty" to anyone else.

Ms Scaffidi and former chief executive Martin Mileham are expected to be called to give public evidence in the coming weeks.