The governing Socialists were joined by the Left Bloc and Communist Party in voting for the bill. Other opposition parties the right-wing People's Party and the centre-right Social Democratic Party voted against.
The original text of the bill was replaced by the governing Socialist Party on Monday with a new version that foresees negotiations with trade unions representing public sector workers on exceptional situations in which the 40-hour week in force for the past year and a half is to be maintained for some employees, in order to "assure the continuity and quality of the [public] services provided."
The new draft does not set a deadline for this to be concluded. In the original text there was a deadline of 31 December for the 40-hour week to be completely abolished.
However, the bill maintains its central thrust, of re-introducing the 35-hour wee gradually over the second half of the year in those services in which the move makes it necessary to hire new staff.
The working week for public sector employees was increased to 40 hours from the previous 35 in September of 2013, with no corresponding increase in salaries, prompting protests from workers and the unions that represent them which have argued strongly against the retention of the longer working week in some sectors in particular health.
The restoration of the 35-hour week is one of the central pledges of the Socialist government, although the minister of finance has repeatedly said that the measure cannot be allowed to increase costs for the state.
According to unions, the increase in the working week was equivalent to a 14% cut in salary.