DLA Piper International is set to merge with its Australian best friend firm DLA Phillips Fox.

The two firms are due to fully financially integrate by 1 May, after terms have been agreed, in a move that will see DLA Phillips Fox become part of DLA Piper's international LLP.

The two firms have had an exclusive referral relationship since 2006, but have now decided to take the arrangement to the next stage. DLA Phillip Fox New Zealand will not be part of the arrangement, but will remain as an exclusive best friends referral firm.

DLA Piper Asia managing partner Alastair Da Costa will become managing director for the Asia-Pacific business, while DLA Phillips Fox chief executive Tony Holland will become DLA Piper's regional managing partner for Australia and will become a member of the firm's executive committee.

The move will see DLA take in revenues of almost £200m from its Asia-Pacific business, which will comprise more than 700 lawyers in Australia, China, Hong Kong, Japan, Singapore and Thailand.

The integration will be put to a vote tomorrow (28 January), with a result expected by the end of February. The combination requires 75% approval from DLA Piper International's equity partnership and 75% of Phillip Fox's overall partnership.

DLA Piper co-chief executive Sir Nigel Knowles (pictured) commented: "The cementing of the relationship between DLA Piper and DLA Phillips Fox is part of our global strategy and is an integral part in helping us become the world's leading business law firm. As part of our strategy we are committed to expansion within the G20 nations, and with Australia as the 14th-largest industrialised nation it provides excellent opportunities with its strong ties to some of the most rapidly growing economies in Asia."

He added: "With the integration of DLA Phillips Fox, DLA Piper will be the world's largest business law firm, uniquely positioning our firm to serve the world's leading enterprises wherever they may conduct business."

Holland said: "We have had a good understanding of the globalisation of business and of the legal market for some time and our affiliation with DLA Piper has enabled us to service clients who are looking to grow internationally. This full integration with DLA Piper will allow us to grow and better meet our Australian clients' increasingly global needs and the needs of DLA Piper's global clients."