In a statement to the Australian Stock Exchange last night, Woodside’s US subsidiary ATS Energy said it had extended its $23 per share offer for EPL to 11:59 Eastern time on October 20.

Woodside’s offer to buy the Gulf of Mexico producer, upgradeable to $24 per share in certain circumstances, had been set to expire yesterday.

The Australian oil and gas exploration giant made the surprise bid for EPL on the condition that its shareholders reject its planned $1.4 billion deal to buy rival Stone Energy.

EPL, which rejected the offer earlier this month as being inadequate and opportunistic, reportedly said the low shareholder response to the offer, with less than 1% of shares outstanding tendered so far, sent a clear message Woodside’s offer was insufficient.

“We will continue to act in the best interest of our stockholders and appreciate the strong level of confidence that they have expressed in our strategy and our management team,” Reuters reported EPL saying.

Instead, EPL's board said it believed that as a stand-alone company or as a combined entity with Stone Energy, the alternatives would provide greater value to stockholders than the Woodside offer.

ATS president Mark Chatterji said he believed EPL was not acting in the “best interests” of stockholders.

“The EPL Board of Directors is telling stockholders to dilute their ownership and incur potentially crippling levels of debt in order to pay a premium to Stone stockholders,” Chatterji said.

“EPL stockholders should be free to choose whether to agree to this recommendation or to instead accept the ATS premium all cash offer.”

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

EPL said earlier this month that it had 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.

The plan involves issuing shareholders rights to acquire one new preferred share for every hundred ordinary shares they already hold. But if any party acquires more than 10% of the company, all other shareholders would be able to convert each right into an ordinary share for half the market price, while the rights may be bought back by EPL's board for just 1c each.

Woodside said that under the ATS cash offer, EPL stockholders would receive a minimum 25% premium to the company's $18.40 closing price on August 25 when the takeover offer was announced.

It noted that EPL's share price has fallen about 10% since that time, reiterating its belief that its offer represented far better value than could be achieved under any deal with Stone, especially considering that world oil prices have dropped in recent weeks.