An EU official said the bloc's foreign ministers had agreed to freeze the assets and impose a visa ban on anyone blocking the inauguration of Alassane Ouattara as the country's president.
Mr Ouattara's electoral win was certified by the United Nations, yet both he and incumbent Laurent Gbagbo have claimed victory and taken oaths of office. Mr Ouattara has been recognised as the legal president by the United States, the EU, former colonial ruler France and the African Union.
The EU official said the measures would be implemented if Mr Ouattara was prevented from assuming office. The most immediate effect of any sanctions would be the withholding of about 213 million in EU development aid.
In Abidjan, security forces loyal to Mr Ouattara fired into the air yesterday after approaching soldiers loyal to Mr Gbagbo, sparking panic that their rivalry had turned to open conflict.
Prime ministerial spokesman Meite Sindou, who belongs to Mr Ouattara's government, said the forces had been sent to remove a roadblock that had been set up by soldiers loyal to Mr Gbagbo. Mr Sindou said no-one was hurt in the brief altercation.