It is best for Slovenia to hold an early election before the summer, she told reporters after a coalition summit at Brdo pri Kranju, about 35 km northwest of Ljubljana, according to Xinhua.
Bratusek made the announcement one week after she failed to be elected as president of Positive Slovenia, one of the ruling parties in the coalition government.
She will officially present her letter of resignation to President Borut Pahor and Speaker Janko Veber Monday.
Bratusek noted that there was no need to panic because of her resignation as the government has managed to stabilise the country’s public finances over the past year, and national economic performance was better than expected.
Analysts said early this week that the coalition government headed by Bratusek would collapse if she resigned, or failed to survive a potential confidence vote.
Bratusek, 43, is the first woman prime minister in the history of Slovenia which declared independence from former Yugoslavia in June 1991.
She was authorised to form a new cabinet after parliament dismissed the coalition government headed by former prime minister Janez Jansa in February 2013.
She declined to talk about her next step after resignation. It was speculated that she might form a new party.