Talisman Sinopec has informed workers it proposes to move to a new three weeks on, three weeks off rota.
It is the latest North Sea operator to warn offshore workers they could face the change to their shifts.
Apache last week confirmed it planned to make the change to its shift patterns from April, and it is understood US firm Marathon Oil is also considering whether to move to a 3/3 rotation.
“Following a working group review, Talisman Sinopec proposes to move to a 3/3 rota, which would deliver essential cost efficiencies in a safe manner,” a Talisman Sinopec spokeswoman said.
“It is our intention to enter into a formal consultation process, and we are currently developing the plans for this and we aim to communicate these to our staff as soon as possible,” she added.
Unions have warned the change in shift patterns from the current two weeks offshore followed by three weeks of leave to three on, three off, will lead to longer hours and compromise safety.
John Taylor, regional industrial officer for union Unite, said recent shift changes and redundancies were announced without consultation, and called for greater engagement from the industry regarding future changes.
Last month Talisman Sinopec announced that 300 jobs from its North Sea operations would go.
The company, which has around 3,000 staff in north-east Scotland, said the losses included 100 employees and 200 contractors.