(Corrects spelling of minister's name)
PARIS, June 13 (Reuters) - A French railway strike entered its third day on Friday and the government said it feared one of the longest stoppages in years could drag into next week, disrupting end-of-school exams for thousands of students.
President Francois Hollande, visiting the Andorra principality wedged between France and Spain, called for an end to the labour union protest over a reform of the railway company structure.
"This does not mean the dialogue cannot continue but the time has come and this industrial action must come to an end," he said.
Rail passengers have seen services cut or cancelled since the strike began late on Tuesday over government plans to bring the SNCF rail operator and the RFF network under the roof of one holding company, while keeping their operations separate.
Unions fear the reform will hurt working conditions and want the two companies fully merged into a single company as they were before 1997. They also want the government to take on some 40 billion euros ($54.5 billion) in debt owed by the two firms.
The government says the reform is needed to create a coherent structure for the railways as France and other European countries gear up for full liberalisation of the railways in coming years.
Transport Minister Frederic Cuvillier said that the hard line CGT and Sud unions had flagged plans to keep up the strike though other less militant unions were backing out.
Rail service disruption could complicate things for students on Monday when the Baccalaureat exams start. The government's education department was working on ways to accommodate late arrivals for the high-pressure exams that mark the exit from secondary school.
While prolonged industrial action would increase pressure on Hollande's Socialist government, it showed little sign of ceding to union demands as legislation on the disputed reform heads to parliament for debate next week.
"In France it's parliament that makes legislation," minister Cuvillier told France Info state radio.
The SNCF rail operator said Eurostar links with Britain and Thalys links with Belgium and further north were expected to run normally, but other international links with countries such as Italy and Spain were still reduced, along with internal high-speed TV train services, down by as much as 50 percent on Friday.
On Thursday four in every 10 trains were running on standard inter-city routes and the SNCF said about 23 percent of staff were on strike - down from 28 percent on Wednesday. ($1 = 0.7345 Euros) (Reporting by Yves Clarisse, Leigh Thomas and Julien Ponthus; Editing by Brian Love and Andrew Callus)