SYDNEY - Former Santos CFO Sherry Duhe says she left Australia's second largest gas producer after just a year due to an "untenable leadership environment" and her differences with long-standing chief executive Kevin Gallagher.

Santos announced Duhe's departure on October 14, less than a month after an $18.7-billion bid for the company led by Abu Dhabi National Oil Company fell apart.

Duhe, in response to a Reuters query on the reasons for her departure from the company, shared a message she sent to some Santos staff and external parties on her decision to leave.

"I gave Santos my best shot but in the end just couldn't reconcile my leadership style to Kevin's," Duhe said in that message.

"Sadly when I initially approached Kevin last week with my intention to resign, he and Kim both asked me to reconsider, and asserted that he wanted to try to improve his leadership style thus that I would stay," the message said.

Kim Lee is Santos' executive vice president people and brand.

"But then I was informed over the weekend by the board chair that my services are no longer needed effective immediately," Duhe's message said.

A Santos spokesperson said the company had nothing to add to its statement to the Australian stock exchange on October 14, in which Gallagher said Duhe was leaving to "pursue other interests". Santos named its deputy CFO, Lachlan Harris, as acting finance chief.

Duhe said she told Santos Chair Keith Spence she had already resigned when he told her her services were no longer required. He then asked her to sign a non-disclosure agreement, but she refused.

"I declined and made clear to him that I would be honest on the reasons for leaving which ultimately boiled down to an untenable culture and leadership environment working for Kevin," she said.

Gallagher has led Santos for almost a decade, during which the company has faced three multi-billion dollar takeover bids which did not proceed. Spence has been Santos' chairman for more than seven years.

Analysts had seen Duhe as a potential successor to Gallagher.

She had previously worked at Shell and Woodside Energy, and was Newcrest Mining's chief executive when it was bought by Newmont for nearly $17-billion in 2023. Santos appointed her as finance chief in September 2024.

The messages sent by Duhe were first reported by The Australian Financial Review.