French police say the simultaneous discovery of groups of Romanian immigrants at Cherbourg and Wexford in the last few days was not the result of any concerted operation by the French and Irish authorities, but consultations are likely to be stepped up in the future.
Cherbourg officials have been watching what was officially called a "well-organised immigrant smuggling ring" for more than a year, but have been unable to stop the flow.
Commandant Yves-Marie Robine, head of the Cherbourg immigration control division, said that Romanians arrested on the ferry docks were all found to hold French residence papers.
"In most cases they have made application for political asylum and try to leave the country for Ireland while their demands are being studied," he said. "Most of these requests are rejected but the applicants are in France legally until this happens".
According to other officials, Ireland is seen as an economic El Dorado and is preferred to Britain as a destination. Illegal traffic with the Republic has been increasing steadily over the past 18 months. Last year 300 Romanians were arrested in Cherbourg after trying to stow away.
So far this year, about 500 men, women and children have been intercepted at Cherbourg where, according to immigration officers, all lorries are systematically searched before being allowed on to ferries.
Last week, 60 Romanians were found. Fifteen of these fled, while the rest were questioned. They were not detained, as their French papers were valid.
They said they had paid about 300 francs (£35) for the crossing to Ireland.
On Sunday a further 70 Romanian would-be stowaways, most of them children, were found in trucks in the port.
In February, a Romanian organiser of an illegal operation was arrested, and later received an eight-month jail term.