European exchange group Euronext has extended the deadline on its 6.8 billion Norwegian crown ($791m) offer for Oslo Bors as the battle with Nasdaq for control of Norway’s stock market operator intensifies. 

Euronext's offer, which had been due to expire yesterday, will now remain open until the evening of May 6. 

The terms remain at 158 Norwegian crowns per Oslo Bors share, a price matched by Nasdaq. 

Euronext said it has secured 53.1% of the shares in Oslo Bors. 

The operator of stock markets in Paris, Amsterdam, Brussels, Dublin and Lisbon said it directly holds 8.1% of the shares and other shareholders have irrevocably pre-committed or tendered 45% of the shares.

The bid battle for Oslo Bors, one of the last independent stock market operators in northern Europe, began in December, when Euronext made a first unsolicited move.

The Norwegian bourse's board's response was to seek new bidders, encouraging US-based Nasdaq to make a rival offer. 

The Oslo Bors board and largest shareholder DNB backed the Nasdaq offer, which will expire on April 30. 

To win over more shareholders in Norway, Euronext has said it will set its commodities trading hub in Oslo. 

The company has said that respected Norwegian financier Tom Vidar Rygh, who has chaired Oslo Bors in the past, has agreed to join the exchange operator's board if Euronext completes the proposed takeover.