Bow said the offer of five of its shares for every seven Roma shares presented a 30% premium for Roma shareholders based on the five-day volume weighted average price of Roma shares on July 8.

QGC had in June offered to pay 10c and 0.0177 QGC shares for each Roma share, valuing Roma at about $50.9 million (or about $47 million at current prices).

"Bow's offer is compelling for Roma shareholders who will receive a substantial premium for their shares and benefit in the future growth potential of Bow," managing director Ron Prefontaine said.

He also took a shot across QGC's bow, saying that Roma's board had to reconsider their previous recommendation of QGC's offer in the best interests of all Roma shareholders.

However, Roma's directors today advised its shareholders to take no action until they had a chance to consider Bow's offer.

Bow said that in addition to Roma's Walloon fairway coal seam methane asset in the Surat Basin - which it believes is the main target for QGC - the company is also keen on integrating Roma's Bowen Basin gas and South Australia Cooper/Eromanga Basin oil business with Bow's current Queensland and Surat/Bowen oil and CSM businesses.

Bow added the combined company would offer the potential for substantial growth when petroleum resources within these assets are developed during a period of strong energy demand and record oil prices.

Bow holds almost 26 million Roma shares, representing about 10.2% of Roma's equity.