Philippe said he wanted a vote in parliament before next summer on the reform, which envisages converging France's more than 40 different pension systems into a single model.
Underlining the risks ahead, employees of the Paris metro operator RATP plan a strike against the pension reform on Friday expected to cause commuter mayhem on the subway and some suburban lines.
France's biggest union, the reform-minded CFDT, is cautiously open to reforming the pension system to make it fairer, but more hardline unions like the CGT are opposed outright and have promised a fight.
"We are ready to take the time that is needed," Prime Minister Edouard Philippe said in a speech in which he is expected to set out how and over what time period his government will reform France's convoluted pension system.
"Nothing is set in stone," he continued.
France was roiled in late 2018 and the first half of this year by sometimes violent anti-government protests against high living costs and Macron's first wave of reforms to liberalise the economy. Macron says he has heard the anger.
Philippe assured unions his government would listen and negotiate, but cautioned: "our determination is total."
Under current proposals, the new pension system would apply to workers born after 1963 and only take effect gradually from 2025, the prime minister said.
In addition to merging the multiple existing pension systems into a single, more transparent points-based system, the reform also aims to close chronic deficits.
(Reporting by Richard Lough; Additional reporting by Leigh Thomas; Editing by Christian Lowe and Andrew Cawthorne)
