They will be joined by workers from throughout the French economy on Tuesday. Both groups are angry at a pension reform the Senate is expected to pass by week's end.
Street protests also are being planned by labour unions on Tuesday and Saturday. Last month, such action brought a million people to the streets of France.
After months of battle over the retirement age, unions upped the stakes by declaring open-ended strikes this time, meaning they could last for days. Past walkouts lasted only one day.
Mr Sarkozy's conservative allies say France must get its finances in better order. Even with the two-year change France would still have among the lowest retirement ages in the developed world.
Unions fear the erosion of the cherished workplace benefit, and say the cost-cutting axe is coming down too hard on workers.
Mr Sarkozy's government is all but staking its chances for victory in presidential and legislative elections in 2012 on the pension reform, which the president has called the last major goal of his term. France's European Union partners are keeping watch, as they face their own budget cutbacks and debt woes.
Early forecasts suggested that railway services, schools, oil refinery production and public transport could be curtailed on Tuesday.
On Monday, French civil aviation authorities urged airlines to cancel 30 per cent of flights at Paris' Charles de Gaulle airport and 50 per cent at Orly airport because of expected staffing shortages. The rail authority expects just one train in three on the high-speed TGV lines, and the Paris Metro is expecting widespread disruptions.
One risk for the government is that students, who wouldn't be affected by the retirement reform for decades, could join the marches out of sympathy for workers.
Mr Sarkozy's government has backed down from at least two reforms planned in education, opting not to incur students' wrath. Potent student-labour coalitions have brought down many planned government reforms over the years in France.
The new nationwide strikes will be the fifth since May, including two last month that coincided with protest marches that drew at least 1 million people into the streets.
The lower house of parliament, the National Assembly, approved the reform last month. The Senate has approved the article on raising the retirement age from 60 to 62, but is still debating the overall reform. The bill also raises the age of eligibility for a full pension from 65 to 67.
Sarkozy, in a small concession Thursday, offered to allow women born before 1956 and who had more than three children to receive full pensions at 65.
That apparently did nothing to stem the strike plans.
