Representatives of regulators in EU members states meeting Monday in Brussels voted unanimously in favour of the fines, two sources said, on condition of anonymity.
EU national regulators are to meet again next Monday to discuss the size of daily fines that could be imposed on Microsoft starting in the coming weeks.
An EU source said that the European Commission would take a final decision on the fines on July 12 or 19, although the first date is more likely.
After a five-year investigation, the commission took its biggest competition decision ever in March 2004 in ruling that Microsoft had broken EU law by using a quasi-monopoly in personal computer operating systems to thwart rivals.
The European Union's executive arm fined the software group a record 497 million euros for abusing its dominant market power.
It also ordered the company to sell a version of its Windows operating system without its Media Player software and to divulge information about Windows needed by makers of rival products.
Although Microsoft has paid the fine, it has fought tooth-and-nail over the information it is supposed to divulge to competitors.
Frustrated that Microsoft has not complied with the ruling, Brussels threatened to slap new daily fines on Microsoft, backdated to December 15 -- its deadline to respect the ruling.
But Microsoft says that it has released reams of key computer code needed by programmers of rival products and claims therefore that further fines go too far.