The change, approved by cabinet last week, brings civil service pay in line with the government’s January-December fiscal year, the Arab News and Saudi Gazette reported.
The reports said the latest austerity measure took effect on October 1.
Saudi Arabia, the world’s biggest oil exporter, is cutting government spending and re-orienting its economy after a collapse over the past two years of the global oil price which provided most of its revenue.
The Hijri calender consists of 12 months of 29 or 30 days depending on the sighting of the moon, meaning the Islamic year is several days shorter than the Gregorian calendar, which is widely used in the world.
Last week, cabinet also cut by 20 per cent the salaries of ministers and froze the wages of lower-ranked civil servants.
Almost twice as many Saudis are employed in the bloated public sector — where hours are shorter and leave longer — than in private firms.
In April, the king’s son, Deputy Crown Prince Mohammed bin Salman, announced the wide-ranging Vision 2030 plan to diversify the economy.
Among its goals, Vision 2030 aims to boost private sector employment, cutting the government payroll to 40 per cent of the budget from 45 per cent by 2020.