A "large majority" of Aviva's 780 strong Greater Manchester workforce are set to be made redundant following the completion of the Friends Life acquisition.
The sites Aviva are looking to close by the end of 2016 are at Manchester Albert Square, Salford Quays and Stretford as part of £225m annual savings by the end of 2017.
The company said motor claims work at Albert Square and Stretford would move to Norwich by the end of next year.
Aviva said it will continue to have a trading presence in Manchester and some staff in Albert Square will transfer to a new city centre office.
It added: "We appreciate this is disappointing and difficult news and we are helping our people through this process, providing a range of support and advice, and consulting with employee representative bodies about these changes."
The Manchester Evening News reported that some staff members were left in tears at the news.
Unite regional officer Andy Case said he is seeking urgent talks with the insurer.
In January Aviva announced that 1500 positions were at threat if the Friends Life acquisition was agreed.
In other changes since the completion of the acquisition Aviva is set to close Friends Life's Salisbury office by the end of the next year with the potential loss of 450 jobs.
Meanwhile, Friends Life Pixham End site in Dorking will close by the end of 2016 with Aviva confirming only some of its 750 staff will move a new site inside the town.
Friends Life Exeter offices will also be closed by the end of 2016.
Aviva said its core UK sites will be in Bristol (where Friends Life's largest office), London, Norwich, Perth, Sheffield and York.