* Public transport, air traffic and ports disrupted
* Senate approves 2nd key clause of pension reform
By Nick Vinocur
PARIS, Oct 12 (Reuters) - French trade unions kicked off a new wave of strikes against pension reform on Tuesday, testing the resolve of President Nicolas Sarkozy's government as the unpopular bill edges closer to becoming law.
Trains, airports and seaports ran below capacity as the unions sought to raise the stakes in their long-running battle against measures whose main feature is a rise the minimum retirement age to 62 from 60.
The nationwide disruptions are a serious test of Sarkozy's leadership as he tries to push through the flagship reform of his presidency. They were expected to reduce flights from Orly airport by half and cut those at Charles de Gaulle-Roissy airport by nearly a third.
One in three high-speed TGV trains on the national rail network would be running, unions said, while around eight out of 10 Thalys trains to destinations including Brussels would operate. The Paris underground is also running limited service.
A series of protests in recent weeks have drawn millions of demonstrators. While the government is betting on them waning, unions hope Tuesday's turnout will exceed the 3 million they said showed up for marches earlier this month.
The protests came after the Senate passed legislation late on Monday that raised the age at which workers can retire on full pensions to 67 from 65.
That vote brought the overhaul of France's pensions system one step closer to reality. The lower house of parliament has already approved the rise in the minimum retirement age.
But union leaders vowed to keep up the pressure.
"This movement will not slow after the Senate vote," Bernard Thibault, head of the CGT union, told I-tele late on Monday.
Limited power cuts targeting public buildings were expected, the union said separately, as energy workers downed tools. Families and students were also expected to join.
Across Europe, austerity measures to trim budget deficits have sparked public anger and protests.
Sarkozy's pension bill is turning into one of the biggest battles of his presidency, pitting him against unions which crushed a previous attempt to reform pensions in 1995.
The reform is aimed at safeguarding France's cherished AAA credit rating, which enables it to borrow at low market rates.
Sarkozy made a small concession in the reform last week to middle-aged women who had given up work to raise children, but his office says he will not back down on the bill's key points.
Meanwhile, port strikes in southern France pressed into their 16th day as workers denounced port reforms as well as the pension bill and forced a partial shutdown of a major refinery.
Key unions have called a further day of protest on Oct. 16.
(Reporting by Nick Vinocur; additional reporting by Helen Massy-Beresford; editing by Noah Barkin)