DLA Piper is merging with Australian partner DLA Phillips, which adds 600 lawyers and creates the world’s largest law firm, which will total more than 4,000 lawyers.

The merger strengthens the formidable Silicon Valley presence of DLA Piper with a focus on M&A — a hot area. [Please see WSJ blogs: DLA Piper: Soon to be the Largest Law Firm in the World – Law Blog]

The firm already has more than 300 lawyers on the West Coast and more than 150 lawyers in Silicon Valley and Bay Area.

DLA Piper was formed in 2005 with the merger of Silicon Valley\CA-based Gray Cary Ware & Freidenrich LLP with Chicago based Piper Rudnick LLP and London-based DLA LLP.

DLA Piper is #1 for M&A deals, with more than  deals in 2010.

[Cross-posted at Silicon Valley Watcher]