WASHINGTON, Nov 21 (Reuter) - The World Bank is pressing ahead with plans for a multi-billion dollar international aid package for Bosnia following the peace agreement struck on Tuesday by the warring parties there, Bank officials said.

Kermal Dervis, department director for the region, told Reuters that the Bank will invite rich nations and other potential donors to a meeting in about a month's time to try to put together a comprehensive assistance programme for Bosnia.

"We've started work already," he said. "Now things will accelerate."

The presidents of Bosnia, Serbia and Croatia Tuesday initialed a peace pact that would end the 3-1/2 year Balkan war and provide for a unified, democratic Bosnian state.

Dervis said potential donors to Bosnia will probably meet in Brussels a few days before Christmas, December 25, to discuss the country's economic needs.

Invitations to the meeting, which the Bank will co-sponsor with the European Commission, will be sent out on Wednesday.

The World Bank group itself is ready to provide significant new net financing to Bosnia for reconstruction and other economic needs as part of an overall aid package, Dervis said.

Much of that could come in the form of low-cost credits carrying no interest charge from the International Development Association, a World Bank affiliate.

"We are agreed at the World Bank group that we will be a significant net contributor to the reconstruction effort in Bosnia ... in 1996," Dervis said.

The Bank has already tentatively identified some $3.7 billion in what it considers urgent reconstruction projects in Bosnian government-held territory alone. Total damage to the region from the war -- Europe's worst in 50 years -- is much larger.

The urgent projects, which would be carried out over the next three to four years, include power stations, bridges and airports.

Next month's donors' meeting is also expected to discuss Bosnia's humanitarian needs and restructuring of its estimated $2.5 billion to $3 billion in overseas debts.

Dervis said that Bosnia is more than $1 billion behind on its loan payments to commercial banks, donor nations and international organisations. Arrears to the World Bank alone amount to $430 million.

Those arrears, plus another $39 million owed to the International Monetary Fund, must be cleared up before the World Bank group can lend Bosnia new money.

Dervis said those arrears could be cleared up through short-term bridge loans from major central banks that would be repaid once an international financing package was in place.