A bill aimed at overhauling Greece’s pension system, which will see Greeks retiring later and receiving lower monthly payments, was submitted to Parliament on Friday as Prime Minister George Papandreou gets set to warn his MPs that if they do not vote for the draft law, he will call a general election.

Labor Minister Andreas Loverdos presentedthe final version of the legislation, which has been considerably reduced and changed over the past few days, after it was approved by the Cabinet.

The changes to the pension system, which will affect anyone who wants to retire as of next year, include an increase in the retirement age to 65. Women had been able to retire at 60 until now. Greeks will also be expected to work a minimum of 40 years rather than the current limit of between 35 and 37 years. This change will be phased in over the next five years but as of 2024, the retirement age will be reviewed every three years and will depend on the average life expectancy in the country.

Anybody seeking early retirement will have their pension cut by 6 percent each month for every year before the new limit that they retire.

“We want to succeed on two fronts, to have a pension system that is viable and fair,” Papandreou told Parliament. “We cannot afford not to move forward.”

Greece currently spends about 12 percent of its gross domestic product on pensions but this figure is predicted to double by 2050 if no changes are made as there will be roughly one pensioner for every working Greek by that time.

Nevertheless, the reforms are unpopular within Papandreou’s own party and sources close to the Prime Minister suggested that he is determined to push them through without having to oust any of his deputies for voting against the bill. Papandreou is set to inform his MPs that if there is even a minor rebellion against the changes, he will call elections.