"We've received an opinion from the Financial Supervisory Authority in which they recommend that both groups, Nasdaq and Euronext, be approved as possible owners of the Oslo Stock Exchange," ministry spokeswoman Therese Riiser Walen told AFP.

It is now the ministry -- which must approve any acquisition of more than 10 percent of the exchange -- which will have the final word.

The ministry is likely to announce its decision by May 14, Riiser Walen said.

Given the unprecedented situation, it is unclear how the ministry will proceed.

The Oslo exchange is one of the few independent bourses left in Europe. Nasdaq and Euronext are each offering around 700 million euros ($785 million) for it, after several attempts to outbid each other.

Euronext, which operates the Paris, Amsterdam, Brussels, Dublin and Lisbon markets, enjoys the support of 53.1 percent of the Oslo exchange's shareholders.

Meanwhile the bid by Nasdaq, which controls all of the other stock exchanges in the Nordic and Baltic region, has the support of the bourse's board and management, as well as 35 percent of shareholders, including the two biggest, Norwegian bank DNB and pension fund KLP.

"Euronext welcomes this positive recommendation from the Financial Supervisory Authority and now awaits final approval from the Norwegian Ministry of Finance which is the last major condition to complete the transaction," the group said in a statement.

"Euronext is convinced it is the best owner for Oslo Bors VPS," its chief executive Stephane Boujnah said.

Meanwhile, Nasdaq said it was "pleased to be have been deemed fit and proper by the Norwegian Financial Supervisory Authority."

"Based on the support by the board and key stakeholders we remain confident that our offer is the best alternative for the continued long-term success for the Norwegian financial markets," Nasdaq said.

Euronext's offer runs until May 6 while Nasdaq's is valid until April 30.