Carlos Ghosn, president and chief executive officer of Nissan voiced his concerns to Blair during a ceremony to mark the first new Nissan Micra leaving the production line in Sunderland.
At the event, Ghosn said that Britain had to join the Euro to ensure the country remained a good place to do business.
Warning that refusing to join the Euro could threaten the company's future in the UK, Ghosn said: 'We have done everything we can to minimise risk. But this is a temporary measure. We cannot continue production in a currency that doesn't represent most of Europe. It's not a question of how strong the pound is. We just do not want currency fluctuations, which only allow you to be profitable if you are lucky.'
Nissan is targeting average lifetime sales of more than 160,000 Micras per year across Europe.