Despite the rejection, Woodside has confirmed to news service Bloomberg that it would not raise the offer.

"The offer is $23 a share, upgradeable to $24 in certain circumstances and that's that," Bloomberg quoted Woodside spokesman Roger Martin as saying this morning.

Australia’s largest publicly traded oil and gas exploration and production company, via its wholly owned subsidiary ATS, last month offered to buy Gulf of Mexico producer EPL for $23 per share in cash.

Woodside said its offer could increase to $24/share under certain circumstances.

Woodside made the surprise bid for EPL, on the condition that its shareholders reject its planned $1.4 billion deal to buy rival Stone Energy.

But EPL’s board yesterday recommended its shareholders not tender their shares to Woodside.

The board said it believes that as a standalone company, or as a combined entity with Stone, the alternatives would provide greater value to stockholders than the Woodside offer.

“The offer is opportunistic and significantly undervalues EPL,” chairman and chief executive Richard A. Bachmann said in a statement.

ATS already owns 4.5% of EPL via acquisitions on the open market in recent weeks.

EPL said in a statement it adopted a shareholder rights plan for a six-month period to defend itself against the bid and allow “sufficient time to act in the best interest” of shareholders.