Perth Lord Mayor Lisa Scaffidi engaged in serious misconduct by failing to disclose gifts and hospitality packages, the Corruption and Crime Commission (CCC) has found.

The CCC investigated a $US36,000 ($50,956) trip Ms Scaffidi took to the Beijing Olympics in 2008, courtesy of BHP Billiton (BHPB).

It found she had "failed in her duties" by not disclosing the gift in her annual return, along with tickets to the 2009 Leeuwin Concert from BHPB and accommodation for the 2008 Broome Cup which she accepted from property management company Hawaiian Investments.

After accepting the Broome hospitality, consisting of three nights' accommodation at the exclusive Cable Beach Club Resort and Spa, Ms Scaffidi voted to approve a $180,000 grant to a consortium, including Hawaiian, for a CBD business feasibility study.

"At no stage did Mrs Scaffidi make an impartiality declaration or disclose the nature of the gift in an annual declaration," the report found.

In 2008, BHPB was likely to become the key tenant of a major new building in the city - although the company was not the applicant or developer seeking council approval.

The company also wanted to use Forrest Place in the city for people to gather and watch the Olympics on a big screen.

BHPB allowed to use Forrest Place for event

The CCC found Ms Scaffidi, having declared an impartiality interest, voted in favour of an application by BHPB to waive a $22,000 fee to use Forrest Place for the event.

Two days later, she accepted all expenses paid trip to Beijing, including business class airfares, which she did not declare on her annual return.

Ms Scaffidi steadfastly maintained that the trip was for "ambassadorial" rather than personal purposes.

"I still hand on heart believe that I was undertaking my role as the Lord Mayor of Perth representing my city and state at an event where one would presume it is good to have attendance by Australians championing the Australian athletes," she told the investigation.

The CCC found that while Ms Scaffidi could have accepted the flights to Beijing if she had declared them, accommodation and tickets to Olympic events were considered "prohibited gifts" under council rules.

"Mrs Scaffidi had considerable involvement with BHPB and knew that they were likely to be a major tenant in the city," the report found.

"The prospect of further dealings over a range of matters including BHPB's sponsorship of the Beijing Olympics should have set alarm bells ringing and at least provoked enquiry.

"There is no satisfactory explanation as to why it never occurred to either Mrs Scaffidi or [former Perth CEO Frank] Mr Edwards on 22 April 2008 that aspects of the Olympic Hospitality Package may be a prohibited gift.

"Either Mrs Scaffidi did not turn her mind to the nature of the gift or she decided to proceed in any event."

Mayor 'deliberately' hid Olympics hospitality package: CCC

It found the mayor had deliberately not disclosed the Olympics hospitality package, and had tried to blame council staff and systemic failings for not disclosing the gifts.

"Attempts to blame others and systemic weaknesses within the City of Perth ignore the fact that Mrs Scaffidi at all times knew where she had travelled," the CCC found.

"In failing to disclose, she signally failed in her duties as Lord Mayor."

The CCC said it did not determine Ms Scaffidi had acted corruptly and it commended her for providing extra details of other travel when its investigation commenced.

However, it said it should serve as a lesson for all public officials.

"To avoid the appearance of bias, gifts worth more than $300 are prohibited if it is reasonable to believe that the donor is undertaking or intending to undertake an activity that requires council authorisation," it said.

"The need to make an annual return is an aspect of open democracy. Anyone can inspect the register. The requirement is a significant accountability measure."

I have worked doggedly to do the best for Perth: Scaffidi

Ms Scaffidi has denied she tried to hide the Beijing Olympics trip, but said in a statement she accepted she failed to comply with relevant provisions in the Local Government Act.

"For that I am truly and deeply apologetic," the statement said.

She said she sought the advice of the then chief executive of the City of Perth before accepting the paid trip from BHP Billiton, who she said supported her decision to go as an ambassador for the city and state.

She said she would make the same decision again.

"It is my work, all in the line of duty," she said.

"I hope that people will see that at all times I have been as open as I could be, and people who know me know that when I travel I have worked absolutely doggedly to do the best for Perth and our city at all times."

She said she welcomed the CCC's findings of no corruption in respect to her conduct.

Ms Scaffidi is seeking a third term as mayor in the forthcoming local government elections, to be held on October 17.

"In continuing to stand, I am here to serve the interests of this city, and that was the purpose at all times of the travel that I have undertaken," she said.

"I believe I am the best person for the job, and given what I have been through, I believe I will be stronger, wiser and even more prepared, and my job is not yet done."

Perth councillor Reece Harley, who is challenging Ms Scaffidi for the mayor's position, said the CCC report was a "serious matter" but he would not comment further.

In May, BHPB was fined $US25 million by the US Securities and Exchange Commission (SEC) for providing hospitality to 176 government officials at the Beijing Olympics on the grounds that it violated the Foreign Corrupt Practices Act.

The US SEC alleged the company had violated anti-bribery and corruption laws when it invited officials who were "directly involved with, or in a position to influence" its business and regulatory affairs.