The firm says the Ho Chi Minh City and Hanoi offices will underline its commitment to continued investment in high growth markets such as Vietnam.

The offices are expected to open in the third quarter of 2012.

Thomas Brown, managing partner of Allen & Overy's Asia Pacific office, said: “Vietnam is rapidly establishing itself as a key jurisdiction within South East Asia and is of increasing interest to international companies and investors.

“We have an unrivalled footprint across the ASEAN region where we are able to advise clients on both international and domestic law in Indonesia, Singapore, Thailand and now Vietnam, as well as bringing our broader network across Asia Pacific to bear,” he said.

Simon Makinson, head of Allen & Overy's Indochina practice added: “We are delighted to be announcing the appointment of Dao, who has succeeded in establishing the leading commercial legal practice in Vietnam.

“Her experience both in Vietnam and the wider region will be invaluable to us and our clients, and she will strengthen the regional team which continues to focus on tapping the huge opportunities across a number of sectors, particularly energy, infrastructure and M&A.”

The addition of Hanoi and Ho Chi Minh City will take Allen & Overy's network to 42 offices in 29 countries.