Company officials were not immediately available to comment.
"The [suspension] decision was taken due to the fact that the new shareholders have not requested and obtained the endorsement of the Commission for Insurance Supervision, CSA, required under the current legislation," the regulator said in a statement.
The business of the company will remain suspended until the CSA approves the new shareholder structure, the regulator said.
Austrian insurance group UNIQA said earlier this month it has wrapped up the acquisition of 100% of Unita from the Vienna Insurance Group (VIG) for an undisclosed sum.
Unita, one of the biggest insurers in Romania, has been majority-owned by VIG since 2001. The company had a market share of 6.12% at the end of June. Its gross premium income grew by 93% last year to 142 million euro ($182.3 million).
($ = 0.779 euro)