The EU is to announce a visa ban and an asset freeze on Belarus President Alexander Lukashenko, diplomats say.
The measures, to be adopted by EU foreign ministers on Monday, will also affect almost 160 of his officials.
Mr Lukashenko remained in power after disputed December elections and four opposition candidates arrested after the vote are still being held.
The sanctions will be imposed on officials "involved in repression" after the vote, diplomats told the BBC.
In the wake of the presidential election, more than 600 people were detained, including seven of the candidates, after protests against what international monitors said was a rigged vote.
Riot police broke up a rally of several thousand people in Independence Square in Minsk.
Sanctions against the Belarusian leader were originally imposed in 2006 after the last presidential election but the travel ban was suspended two years later in an attempt to encourage reforms.
The original measures were also targeted at 40 associates and the decision to extend them to almost 160 officials is being seen as an effort to include people involved in election fraud as well as what diplomats describe as "repression of civil society and independent media".