Shares in Salamander, which first put itself on the block in May, rose as much as 24.6 percent, making them the top percentage gainers on the London Stock Exchange on Monday morning.

A consortium led by Spanish firm Compania Espanola de Petroleos (CEPSA) and Jynwel Capital has also approached Salamander. However, the consortium has not given any details of its proposal or any confirmation that an offer would be made, the London-listed company said.

Salamander, which had a market capitalisation of about 207 million pounds (206 million pounds) at Friday's close, said it was in discussions with Ophir and the CEPSA consortium regarding their proposals.

Under UK takeover rules, the bidders have until Nov. 24 to make clear their intent either to make a firm offer for the company or to walk away. The deadline could also be extended if the firms make such a request.

The Sunday Times reported that Ophir Energy and Spanish rival CEPSA were preparing competing takeover bids that could value Salamander at over 275 million pounds ($442 million).

"(Ophir and Salamander) may be a financial fit but, at first sight, it is difficult to see where significant value could be added. Ophir shareholders may prefer to put their own assets in the shop window," Liberum analysts said in a note.

However, the analysts said that despite the geographic disparity between Salamander and Africa-focused Ophir, Nick Cooper, CEO of Ophir, should know Salamander's assets well as he was CFO of the company at the time of its listing.

Ophir said in a separate statement that it planned to buy interests in seven deepwater exploration assets from Niko Resources Ltd for $31.3 million upfront, making it the leading deepwater exploration acreage holder in Indonesia.

Shares in Salamander were up 21.5 percent at 97.50 pence at 0859 GMT, while Ophir's stock was down 3.3 at 196 pence.

(Reporting by Esha Vaish and Roshni Menon in Bangalore; Editing by Gopakumar Warrier)

Stocks treated in this article : Ophir Energy Plc, Salamander Energy Plc