Berlin - Berlin will announce Monday details of how Germany is to commit hundreds of billions of euros to a rescue plan for the world economic system, with Chancellor Angela Merkel expected to speak to the media in the afternoon.

Sources said she and the two leading Social Democrats in her coalition government had agreed in the night on the basics of the plan, with the next move being to discuss it in cabinet.

The two Social Democrats, Finance Minister Peer Steinbrueck and Foreign Minister Frank-Walter Steinmeier, will be key in securing parliamentarians' support for a rapid passage of the bill.

Together, Merkel's Christian Democrats and the Social Democrats have an overwhelming majority in the Bundestag lower chamber.

The chief of the Christian Democrat caucus, Volker Kauder, said on ARD public television he expected the guarantees and liquidity infusions to total 400 billion euros (550 billion dollars) but government officials have not offered any firm figures yet.

Merkel was expected to address the media at 3 pm Berlin time (1300 GMT) with her remarks to be broadcast live on all-news television.