Dimic said in an emotional letter that the decision was made because the need to reject or explain the condemnations in the public does not allow her to fully dedicate herself to the demanding job of the head of the prime minister's office.
The Corruption Prevention Commission said on Tuesday it had begun two probes but would not specify on what grounds Dimic is being investigated, saying that details cannot be disclosed during the course of the investigation.
Dimic has been the subject of various media reports about the assets of herself and her partner, businessman Roman Horvat, in recent days.
Public broadcaster RTV Slovenija said last week that revenues of Horvat's tourism firm, Escape, rocketed in the first year of the Pahor government. According to business daily Finance, the government has sought the company's services in making flight arrangements for officials.
Media have also reported on the renovation of Dimic's house in a wealthy Ljubljana suburb of Murgle, which was reportedly funded with a EUR 350,000 loan from the state-owned bank NLB under favourable terms.
Further speculation has since arisen about the construction firm that performed the works. RTV Slovenija quoted workers of insolvent builder Vegrad as saying they had performed the work using material taken from the site of Vegrad's massive flat complex in Ljubljana. Dimic had denied that Vegrad renovated the house.
Pahor told said on Wednesday that he still trusted Dimic despite the announcement from the anti-graft body, adding that any decisions on her future would be taken after the commission returned its opinion in probes about Dimic's actions.