Patten, whose experience includes senior in-house counsel roles for Shell Gas & Power in London and Dubai, has been an energy partner at Ashurst since 2008.

Beginning his career in Allens' Melbourne office, Patten kept in regular contact with a number of Allens partners while working in Ashursts' energy, transport and infrastructure team.

"We've worked with him at times in different capacities since he left," said Allens Perth practice director, Andrew Pascoe.

"It's a very exciting proposition, not just for our firm but for the Western Australian market generally, that experts of his calibre are seeing this as the place to be to further their career in the oil and gas sector," said Pascoe, noting Patten's desire to make his return to Australia in the "regional hub for the peak oil and gas work globally".

"With $100 billion in expenditure already committed in the oil, gas and liquefied natural gas industries in Australia alone, the variety, complexity and quality of work in the Asia region is second to none," said Patten.