Earlier this month, Ophir rejected Medco's $437 million potential buyout offer based on 48.5 pence per share saying it undervalued the company and that Medco had initially mooted 58 pence per share.

Ophir's shares lost almost half of their value last year as it failed to find financing for a liquefied natural gas project in Africa's Equatorial Guinea.

This led to it losing its licence for the project prompting it to warn of a $300 million write-down for the full year.

Ophir's current output of 25,000 barrels per day (bpd) of oil equivalent combined with Medco's stated 2018 target of 85,000 bpd of oil equivalent would make Medco, which has been expanding, the seventh largest non-national oil company upstream producer in Southeast Asia, according to research firm WoodMac.

(Reporting by Sangameswaran S in Bengaluru and Shadia Nasralla in London; Editing by Gopakumar Warrier and Emelia Sithole-Matarise)

Stocks treated in this article : Medco Energi Internasional Tbk PT, Ophir Energy Plc