The minister described the bidders as prominent and highly skillful energy companies, and expressed satisfaction with the first round of the tender.
The government will select the best bids by the end of this year, and contracts are likely to be concluded by the end of the first quarter of 2015.
The head of the Croatian agency for hydrocarbons, Barbara Doric, said that the evaluation of the bids would start on Tuesday and that the bidders' identity would not be revealed for the duration of the evaluation process.
On 2 April, Croatia's Economy Ministry published an international tender for oil and gas exploration in the Adriatic Sea, saying that the tender would run until 3 November.
In April, Vrdoljak officially presented the tender entitled "1st Offshore Licensing Round for Licences for the Exploration and Production of Hydrocarbons" at a conference in Zagreb which brought together executives of dozens of petroleum companies such as Exxon, Gazprom, Lukoil, Total, Ina, RWE, Edison, Turkish Petroleum, Hellenic Petroleum, Petroceltic, Hunt Oil, JP Nippon and others.
The tender defines 29 exploration blocks, eight of which are in the north Adriatic and 21 in the central and southern Adriatic regions. The size of the blocks ranges between 1,000 and 1,600 square kilometres.
The propositions of the tender made it impossible for the press to learn today which blocks the received bids referred to.
Both Vrdoljak and Doric said they hoped more bids would be submitted in the next tender round, as is usual in such procedures.
During the seven-month period of the tender, 45 companies visited the Zagreb-based data room containing surveys of Croatia's part of the Adriatic Sea and 18 of them bought documentation paying 15 million kuna to the Hydrocarbons Agency, Doric said.
Upon the start of exploitation, 55% of earnings will go to the state and 45% to the investor, according to Doric.
The exploration process includes the preparation stage that can last three to six years, during which it should be established whether the area concerned has enough oil or gas reserves for commercial exploitation.
Asked by the press about outstanding issues with Montenegro regarding border demarcation at sea and boundaries around the blocks, Minister Vrdoljak said that Croatian authorities were in touch with their Montenegrin counterparts and that both sides were willing to solve those issues.