Suitor Aurora Oil & Gas has appointed three representatives to takeover target Eureka Energy's board after increasing its stake to 68.4 per cent.

Eureka's current board of Ian McCubbing, Mark Wilson and Bill Bloking have all quit.

Aurora has also extended the offer period for its US$107 million ($105.35 million), 45 cents a share bid until 6 July.

Both companies are US-focused shale oil and gas explorers and producers operating in the same liquids rich Eagle Ford shale basin in the US where BHP Billiton holds shale assets.

Eureka's board initially resisted the bid in late April, arguing it undervalued the company, but by last week all three directors had changed their mind and recommended that Eureka shareholders accept it.

The three new Eureka directors include Aurora's executive chairman Jon Stewart and fellow Aurora directors Ian Lusted and Graham Dowland.

Roger Steinepreis will join Eureka as an independent non executive chairman with a second independent director to be appointed.

Mr Stewart said Aurora would review Eureka's asset portfolio and its capital structure.

"Our offer for Eureka builds on our already strong presence in the Sugarkane Field where we are Marathon's largest partner and is consistent with Aurora's stated growth strategy," he said in a a statement.