By Imogen Foulkes
BBC News, Berne
If voters say no, borders will be harder to cross for non-Swiss workers
Swiss voters are going to the polls to decide whether to continue allowing in workers from the European Union.
More controversially for many Swiss, they will also vote on whether to extend that free movement to new EU members Bulgaria and Romania.
Switzerland remains outside the EU - but its political and economic ties to Europe are very close.
A "no" to free movement could put that relationship at risk. Opinion polls indicate the vote will be close.
Since the Swiss first introduced free movement of labour the number of EU citizens working in Switzerland has risen to over a million.
Business leaders like Rudolf Staempfli say the policy has brought only benefits, despite doubts at the time.
"They suggested we wanted the cheap Polish worker in Switzerland, but the opposite has come true, we took skilled expensive workers," he said. "We do have a subsidiary in Poland, with swiss workers there. "
But that first decision to allow in EU workers was taken during an economic boom - things are different now. Hans Fehr, member of parliament for the right-wing Swiss People's Party, claims extending free movement to Bulgaria and Romania could bring a mass influx of cheap labour.
"Now we are in a recession, very hard - for Swiss businessman it is important to have low-paid workers and that is very dangerous for Swiss workers, maybe they lose their job," he says.
Opinion polls show the vote will be close - but a no vote could carry risks.
Switzerland may not be in the EU, but it needs a good relationship with Brussels - one in every two Swiss francs is earned through trade with the EU, and one in every three Swiss jobs depends on that trade.
Brussels has made it clear the Swiss can't pick and choose EU policies - rejecting free movement could threaten those crucial trade ties.