Portugal slashed its public sector deficit by more than half in a single year, when measured as a proportion of GDP, the national statistics bureau has said, taking the shortfall comfortably below euro zone limits.

The deficit dropped to 2.1%  of gross domestic product in 2016, a staggering reduction from its 4.4%  level a year earlier.

This confirms Finance Minister Mario Centeno's prediction last month that the deficit would be "not more than 2.1%", its lowest share of GDP since the advent of democracy in 1974.

Euro zone members are required to keep their public deficits to below 3% of GDP, but some are struggling to do so.

Portugal's public deficit shot up into the double digits during the global economic crisis, and despite an international bailout it had difficulty bringing it back down to 4.4% in 2015.

Portugal's economy expanded by 1.4% in 2016, the national statistics institute said in February, after growing by 1.6% the previous year on the back of stronger exports and private consumption.

Meanwhile, the French government cut the public sector deficit last year slightly less than planned, data from the INSEE official statistics agency showed.

INSEE said in a preliminary estimate that the deficit fell to 3.4% of GDP in 2016 from 3.5% in 2015, revised from 3.4% previously.

The result fell short of the government's target to cut the deficit to 3.3% last year.

Finance Minister Michel Sapin said in a statement "the conditions are in place" for the deficit to fall in line with an EU limit of 3% this year.