Nissan chief Carlos Ghosn has repeated warnings that its Sunderland plant could lose production of one of its most important cars if Britain remains outside the euro.
Mr Ghosn, Nissan president and chief executive, made his comments during a round table meeting with journalists at the Detroit Motor Show.
The company, which employs 4,500 workers at its flagship plant on Wearside, today stressed that it was not the first time Mr Ghosn had warned of investment problems if Britain did not join the single currency market.
The Wearside plant currently makes the company's mid-size Almera model, but decisions have to be made on where its eventual replacement will be built.
A Nissan Motor Manufacturing UK (NMUK) spokesman said today: "Mr Ghosn has been very consistent in what he has been saying in response to questions about the single currency issue.
"The UK's exclusion from the euro adds an element of unpredictability when having to make an investment decision.
"Given the high cost of investment involved when introducing a new model, this lack of long term economic visibility is one of several factors that have to be taken into consideration when deciding where to site production of future models for sale in Europe.
"Every new model is subject to a thorough manufacturing feasibility study before any production decision is taken.
"If the UK is still outside the eurozone when the next decision on new model allocation has to be made (not before 2005), this will be one factor that will be considered as part of that study - together with logistics, production cost, manufacturing efficiency etc.
"On a local level, NMUK is doing what it can to offset any disadvantages caused by the UK's exclusion from the single currency by working to become the best it can possibly be in terms of cost, flexibility, productivity and efficiency.
"As with all new models, NMUK will endeavour to attract the replacement to the Almera on this basis."
Nissan opened in Sunderland in 1984 and the first Nissan Bluebird car rolled off the production line in 1986.
By 1992 the total investment in NMUK reached £900 million, the largest single Japanese inward investment in Europe.
By 1995 the plant had produced its one millionth vehicle and by 2002 total plant production had exceeded three million vehicles.
Last year the World Markets Research Centre identified the plant as the most productive in Europe for the seventh consecutive year, and in December it was announced that the Sunderland plant would start work on a coupe/cabriolet version of the Micra (called C+C) from autumn 2005.Reuse content