The move is part of a wider global restructuring plan for Infiniti.
Nissan canceled plans in February to build a new diesel-powered X-Trail sports utility vehicle in Sunderland. Just 170 of the pair were sold in Australia past year, with the marque notching up just 649 sales in total.
Infiniti will withdraw its manufacturing and sales operations from the United Kingdom in 2020 as it targets electrification and growth in Western Europe, China and the US.
Infiniti will continue selling cars in Russian Federation and eastern Europe, it said.
Infiniti cars failed to catch the imagination of European buyers and production will halt in the summer.
"Working to find alternative opportunities for any employees who would be affected, consulting with employee representatives where necessary and identifying opportunities for transition and training support where appropriate", the company said in a statement.
Unite's national officer Steve Bush said: "This decision, which is driven by poor sales, is obviously sad news".
The Japanese vehicle maker said the move was part of plans to withdraw from the premium auto market in western Europe, where the Infiniti brand faces stiff competition from local rivals including Jaguar Land Rover, Audi, BMW and Mercedes-Benz.
"Western Europe remains the most challenging and competitive region for premium cars", Infiniti's chief spokesman, Trevor Hale, said.
Responding to today's announcement, Unite said it would be seeking assurances on future employment and was confident of securing redeployment opportunities for the 200-plus workers affected.
Sunderland is now the only Nissan plant building Infiniti's Q3 and QX30 models.