Saudi Arabia's deficit widened significantly to $15.65 billion in the first quarter of 2025 from $3.30 billion a year before as oil revenues fell 18% to 149.810 billion riyals ($39.95 billion), its finance ministry said on Monday.

The world's top oil exporter and de-facto OPEC leader saw its total revenues drop 10% to 263.616 billion riyals in the first quarter, while its public spending rose 5% to 322.317 billion riyals.

Declining oil prices and voluntary production cuts have weighed on Saudi revenue in recent years as Riyadh pushes ahead with strategic spending on projects linked to Vision 2030, the kingdom's ambitious plan to overhaul its economy and wean off its dependence on oil.

The kingdom's non-oil revenues rose 2% in the first quarter from a year earlier to 113.806 billion riyals.

Saudi Arabia was one of eight members of OPEC+ - which includes the Organization of the Petroleum Exporting Countries and allies led by Russia - that agreed in April to speed up a plan to phase out oil production cuts by hiking output in May.

The kingdom forecast a budget deficit of 101 billion riyals in 2025 as it moves onward with its plan to boost growth and deliver on an economic transformation that requires hundreds of billions of dollars in investments.

Saudi public debt reached 1.329 trillion riyals in the first quarter of the year. The kingdom, which enjoys a low debt-to-GDP ratio and confidence from lenders, was among the largest emerging market debt issuers in 2024.

It is allocating hundreds of billions of dollars to fund large-scale development projects aimed at reducing its reliance on oil, while fostering growth in tourism and the private sector.

Boosting non-oil economic growth remains a top government priority, with the kingdom stepping up efforts to attract investment into tourism and expand the private sector.

In November, Saudi Arabia approved its state budget for 2025 forecasting a fiscal deficit of 101 billion riyals.

($1 = 3.7504 riyals)

(Reporting by Ahmed Elimam and Nayera Abdallah; Writing by Yomna Ehab and Mania Saini; Editing by Louise Heavens and Jan Harvey)