Santos said on Tuesday that CFO Sherry Duhe has resigned, just one year after taking on the role, as the Australian gas producer navigates a transitional period ahead of the startup of its key Barossa and Pikka projects.

Duhe, a former senior executive with Australian oil and gas producer Woodside Energy and gold miner Newcrest, was appointed in September last year amid speculation over a potential leadership change at Santos.

Current Deputy CFO Lachlan Harris has been named acting finance chief. Harris brings prior experience in various finance roles across the company.

The sudden departure without a meaningful explanation can be seen as another red flag regarding Santos governance, said Saul Kavonic, a senior energy analyst with MST Marquee.

"The resignation comes as Santos is traversing its most acute balance sheet position ahead of startup of Barossa and Pikka, and after XRG walked away."

Shares of Santos were down 0.4% at A$6.445, as of 0030 GMT.

After an extensive investment cycle, Santos' $4.5 billion Barossa gas project off northwestern Australia and the $3.1 billion Pikka oil project in Alaska are nearing their first production and expected to contribute significantly to cash flows.

Analyst Kavonic pointed out that Duhe's departure leaves Santos without a clear succession plan, as she was widely viewed as a potential successor to CEO Kevin Gallagher should he choose to step down.

Gallagher has overseen three failed takeover bids for Santos over the past seven years, fuelling speculation about his future as CEO.

Last month, Gallagher said he has no plans to retire and expects cash flow to improve significantly in the next few years following the start of the two new projects.

A few weeks ago, a consortium led by Abu Dhabi National Oil Company's overseas unit XRG walked away from an $18.7 billion offer for Santos after months of wrangling over valuation and terms.

(Reporting by Sneha Kumar in Bengaluru; Editing by Shreya Biswas and Sherry Jacob-Phillips)