Despite record-high domestic harvests in recent years, including last year's output, the Southeast Asian country remains one of the world's biggest rice buyers, with neighbours Vietnam and Thailand its traditional suppliers.
The National Food Authority (NFA), which acts to ensure food security, said it would seek up to 500,000 tonnes of well-milled long-grain white rice through government-to-government deals to build up stocks ahead of the lean harvest season starting in July.
The agency is seeking up to 250,000 tonnes of 25 percent broken rice and 250,000 tonnes of the 15 percent broken variety, with half of the volume for delivery not later than March 31 and the rest not later than April 30, it said in a statement.
Countries with existing supply agreements with the Philippines such as Thailand, Vietnam and Cambodia are qualified to submit offers, which would be sought from this month.
Fresh demand from the Philippines could provide support for export prices in Asia, which have been under pressure from thin demand and rising supplies.
The NFA also said it aimed to buy 189,845 tonnes of paddy rice from local farmers from January to June this year, the highest volume since 2010, when first-half purchases totalled 230,965 tonnes.
The agency imported around 1.7 million tonnes in 2014, the biggest amount in four years, as local supplies were tight due to natural calamities, pushing food price inflation to the highest level in more than five years.
Local unmilled rice output may rise 2 percent to 8.55 million tonnes in the first half from the same period last year, based on the latest forecast of the Bureau of Agricultural Statistics.
The NFA began the year with a buffer stock of around 520,000 tonnes, sufficient for 15 days. It needs to double that figure during the lean harvest season.
Imports this year could reach 1.6 million tonnes, according to a forecast by the United States Department of Agriculture, although a government source said last month that purchases could be less than 1 million tonnes.