Workers at Rouen, Le Havre, Ouistreham, Dieppe and Cherbourg are taking part in a national strike organised by the National Ports and Docks Federation and the powerful CGT union.
The strike is likely to cause disruption to freight traffic rather than car passenger ferries, officials said.
The action was called after French junior minister for transport Frederic Cuvillier, who has responsibility for the maritime economy, was unable to offer any assurances about the financial outlook at a meeting at the beginning of the week.
The Federation says that workers have already accepted the privatisation of ports which began in 2008 but now a lack of investment in the ports themselves and their surrounding areas is threatening their economic future.
The amount of traffic going through ports is falling. Some of the ports in Normandy, most notably Dieppe, are also concerned about the future of cross channel services.
â€˜For a year now the National Federation of Ports and Docks has sought reassurances from the transport minister Frederic Cuvillier about the problems ports are facing. We have met with the minister and passed on our concerns about the volume of traffic in French ports and we have repeated that we are waiting for a response from the government,â€™ the federation said in a statement.
â€˜The Federation has also asked about dwindling freight levels and the need for investment in ports and their hinterlands. We have still not received any answers to our questions,â€™ the statement continued.
Officials also believe that although Mr Cuvillier may have the best intentions he has failed to secure a case for French ports to be part of a wider investment at European level in the development of rail corridors to develop and increase trade with ports in northern Europe.
They want him to stand up for French ports and insist that they should not suffer as part of Francois Hollandeâ€™s austerity measures.