The carmaker chose to shift production of its Q30 unit to Japan amid weak sales in western Europe, with work due to conclude in Sunderland "by mid-2019".
Infiniti said an exit from western Europe will allow it to focus on its initiative to "electrify" a good portion of its product portfolio from 2021 and discontinue diesel offerings.
Unite said it would be seeking assurances on future employment and was confident of securing redeployment opportunities for the 200 plus workers affected.
The brand plans to focus more on its SUV lineup in North America, bring five new or significantly-redesigned vehicles to China over the next five years, improve quality of sales and residual value and realise more synergies with Nissan.
'Nissan has reiterated its commitment to the United Kingdom and its workforce by continuing to manufacture in Sunderland the current Qashqai, Leaf and Juke models, as well as the new Qashqai model'.