A press conference has been scheduled for noon today, in which World Service will confirm the closure of five foreign language services in a bid to save around £46m a year. The Macedonian, Albanian and Serbian services will be axed, along with English for the Caribbean and Portuguese for Africa.
The World Service currently costs £272m a year to run and has an audience of around 241 million people across radio, television and online services around the world.
However, the division is facing a 16% cut to its grant-in-aid funding from the UK's Foreign & Commonwealth Office between now and 2014 as part of the comprehensive spending review. The BBC will take over funding for World Service from 2015.
Today, BBC World Service director Peter Horrocks is expected to announce up to 650 job losses from the division's 2,400-strong workforce. It is understood that around two-thirds of the jobs will go in the next 12 months, with the remainder going in the following year.
The World Service cuts will take the number of BBC job losses announced this week to around 1,000, following Monday's news of 360 posts to be closed at BBC Online.
In a statement, Horrocks stressed that the cuts at World Service were "not a reflection on the performance of individual services or programmes".
Discussing the service closures, Horrocks said: "They are all extremely important to their audiences and to the BBC. It is simply that there is a need to make savings due to the scale of the cuts to the World Service's grant-in-aid funding from the UK's Foreign & Commonwealth Office and we need to focus our efforts in the languages where there is the greatest need and where we have the strongest impact."
However, the National Union of Journalists (NUJ) intends to stage a demonstration outside the World Service headquarters at Bush House in central London today to protest the cuts.
Prominent members of the union have also written to Richard Ottaway, the chairman of the House of Commons Foreign Affairs committee, and John Whittingdale, the chairman of the Culture, Media and Sport Committee, calling on them to review the "drastic" plans. In the letter, the NUJ members said that Horrocks's strategy for World Service will "severely damage the national interest of the UK".
NUJ general secretary Jeremy Dear added: "These ferocious cuts to a valued national service are ultimately the responsibility of the coalition government, whose policies are destroying quality public services in the UK."