The former head of Allens' Singapore office Marae Ciantar has joined local outfit Rajah & Tann to lead the 20-lawyer energy and resources group.

Ciantar, who played a key role in growing the Australian firm's clientbase in South East Asia, was the last Allens partner to leave the Singapore base after the tie-up with magic circle firm Linklaters saw the two firms combine offices in the island state.

He is understood to have exited Allens at the end of last year, making him one of 11 lawyers and four partners to go since the beginning of 2012.

Other departures from the Singapore hub included disputes lawyer Matthew Skinner and energy expert Darren Murphy, both of whom joined Jones Day in October 2012, followed by banking and finance partner Rod Howell, who joined Herbert Smith Freehills in February 2013.

Ciantar joined the Australia firm in Melbourne in 2000 and made partner eight years later.

He initially headed the firm's Cambodia practice from capital Phnom Penh, before moving to Singapore in 2010 alongside Howell, who joined from Clifford Chance, Murphy, who relocated from Allens' Perth base and Skinner, who moved over from Sydney.

He later led the firm's efforts in Myanmar, splitting his time between the two places, and worked on a number of major energy and resources projects across the South East Asia region.

He joins Singapore-headquartered Rajah & Tann as it continues its push towards becoming a premier ASEAN specialist firm.

Earlier this month it hired 14 lawyers in Bangkok from US outfit Hunton & Williams, and in February tied-up with Vietnamese firm LCT Lawyers.

Last year it also launched partnerships with NK Legal in Myanmar, R&T Sok & Heng in Cambodia, Assegaf Hamzah in Indonesia and Christopher & Lee Ong in Malaysia.

Recruited to work with Ciantar is energy lawyer Ashley Phelps, who will be appointed as a senior foreign law associate.

Phelps has extensive experience in resources and construction, after previously working on major projects with both Baker & McKenzie and Allens and most recently being employed as in-house counsel at the Cambodian National Petroleum Authority.