By Kirsty Needham

SYDNEY (Reuters) -The former premier of Australia's most populous state engaged in corrupt conduct involving another lawmaker with whom she was in a secret romantic relationship, a years-long corruption inquiry that examined business dealings with China said on Thursday.

The New South Wales Independent Commission into Corruption (ICAC) said in a report handed to parliament that Gladys Berejiklian had failed to notify the commission of her concerns that Daryl Maguire, a member of parliament with whom she was in a relationship during her term of office, may have engaged in corrupt conduct, and this undermined the ministerial code.

As NSW premier in 2020 Berejiklian, once a star of the Liberal party and widely respected for her leadership during the COVID-19 pandemic, told the corruption inquiry she had been in a secret "close personal relationship" with Maguire, who was under investigation for monetising his position through business dealings with China.

A year later she resigned when the watchdog said it was investigating whether she was involved in conduct that "constituted or involved a breach of public trust".

Berejiklian, who could not be immediately reached for comment, has denied any wrongdoing.

Maguire told the inquiry he had received envelopes full of thousands of dollars in cash at his parliament office as part of a scheme for Chinese nationals to fraudulently acquire visas.

The commission found Maguire engaged in "serious corrupt conduct" between 2012 and 2018 for the migration scheme and other misconduct.

It said he misused his role as chairman of the NSW Parliament's Asia Pacific Friendship Group to advance the commercial interests of a Shenzhen business association in South Pacific nations.

He was also found to have monetised his position as a lawmaker to benefit a company, G8way, which sought to sell access to "high levels of government" in Australia. G8way's "man in Beijing" was a former vice consul in Sydney, it said.

Maguire also misused his office by receiving a fee to introduce the party secretary of Liaoning province in China to then NSW premier Barry O'Farrell at parliament in 2012, it said.

Maguire already faces a criminal charge for his role in the visa scheme, for which he has not yet entered a plea in court. His lawyer said in a statement the commission is "not authorised" to make findings that a criminal offence has been committed.

The commission said it would seek advice from the Director of Public Prosecutions on whether further prosecutions should be commenced into Maguire.

(Reporting by Kirsty Needham; Editing by Stephen Coates)