Portugal's President Anibal Cavaco Silva said Saturday he has asked the constitutional court to rule on whether pension cuts provided for in the controversial 2014 austerity budget are legal.
The planned 10 percent reduction in pensions affects retired civil servants who are drawing more than 600 euros ($800) a month.
If the court rules against the measure due to come into effect January, it would deprive the centre-right government of some 728 million euros in savings -- or about a fifth of the total planned spending cuts.
The constitutional court has already ruled against several austerity measures.
The court has 25 days to issue its verdict.
Eurozone member Portugal has had to undertake draconian measures to reduce its public deficit and increase the efficiency of its economy in exchange for some 78 billion euros in rescue loans.
The bailout programme lasts for three years with the intention that next year Portugal will have re-built sufficient credibility to be able to finance its deficit and debt on the sovereign bond market.