Aker Solutions said employees had been told about 650 positions, mainly in the UK, Norway and India, may be affected.
A more specific breakdown for Aberdeen and London jobs has not been announced.
A spokesperson said: "The adjustments are being made because of the continued market slowdown and as part of a global reorganization that will strengthen the company's competitiveness."
Aker employs about 15,000 people, of which more than 2,000 are in the UK, the majority of them in Aberdeen and offshore.
Hundreds of jobs are set to go at oil services firm Aker Solutions with about 100 at risk in Aberdeen and London.