Sri Lankan President Ranil Wickremesinghe granted amnesty to nearly 800 convicts to mark the traditional Sinhala and Tamil New Year on Saturday, his office said.

The amnesty of 779 inmates followed the release of 1,000 prisoners to mark Christmas.

A prisons official told AFP that a recent spate of amnesties had eased congestion in the island country's still-overcrowded jails. 

As of Friday, there were just under 30,000 inmates in Sri Lankan prisons, which were designed to hold around 11,000 people. 

Sri Lanka has declared a long holiday for the New Year and banned the sale of alcohol until Tuesday.

This year's celebrations were marred by conflicting timetables announced by an official panel of astrologers assigned to decide on a schedule for traditional ceremonies.

The government has asked citizens to follow the decision of a majority 42 astrologers, who said the public should light a stove and make their first meals of the year just after midnight.

The dissenters, however, say it should be done on Sunday morning at a "godly hour", warning that if their timetable warning was not followed, a great misfortune would befall the island nation, which is emerging from an unprecedented economic crisis.

Astrologers are hugely influential figures consulted by both the island's Buddhist and Hindu communities, and their verdicts on auspicious dates guide everything from marriages and business deals to national election timetables.

Former president Mahinda Rajapaksa called a snap election in January 2015 based on a date advised by his personal astrologer, but went on to lose the polls.