The Philippines launched a 10-year dollar bond offer on Wednesday, which a source said could be for about $1 billion, marking the first offshore issue in Asia this year.

The government has said it wants to raise much of its 2009 overseas commercial borrowing needs of $1.5 billion in the first quarter.

"We have already launched the offer," National Treasurer Roberto Tan told Reuters. "It is a benchmark-sized offer due in 2019." He gave no details on pricing.

A source close to the deal said the offer could be about $1 billion, but Tan said no decision had been taken on the offer size.

"It will depend on the market," he said.

The size of the offer would be decided soon after the Philippines finishes its book-building exercise, which could come late on Wednesday in time for the opening of New York trades, another source close to the deal said.

Analysts have said Manila could be looking to raise funds to to refinance sovereign bonds worth about $935 million that mature in March.

The offer will be managed by HSBC, Credit-Suisse and Deutsche Bank, the source close to the deal said.

It is the third major issue of offshore debt so far this year, but the first from Asia.

Colombia launched a 10-year global bond on Tuesday while Brazil's treasury also said it had launched a 10-year bond on Tuesday.

The Philippines, one of Asia's largest sovereign debt issuers, also plans to borrow $1.1 billion in official development assistance loans this year.

It aims to raise $8.2 billion in the domestic debt market to fund a budget deficit seen widening to 102 billion pesos ($2.2 billion) from as much as 75 billion pesos in 2008.

Tan has previously said the Treasury was also planning to issue retail treasury bonds or increase the volume of its domestic debt offers to cover maturing local debts in February. It can also opt for a domestic bond swap.