French hauliers decided last night to maintain their blocking of frontier posts, motorways and main roads today in protest at the price of fuel and the introduction of a 35-hour week.

Border posts into Italy, Germany, Spain and Belgium were blocked as hundreds of trucks took part in the first day of action by lorry owners yesterday. Police warned that the situation would probably be worse today.

The worst chaos was in the north, where protesters disrupted traffic on the main routes south from the Channel ports by setting up roadblocks or driving at low speed in three lanes.

Access was left open to Calais and Boulogne, but truck owners made it difficult for cars to board the cross-Channel ferry at Le Havre.

The owners' spokesman, Stéphane Levesque, said a 35-hour week would put businesses "at a further disadvantage" compared with other EU countries.

But drivers' unions have told the transport minister, Jean-Claude Gayssot, that concessions over the 35-hour week would lead to a counter-strike by employees.