Top law firms are forking out more than $5 million a year to poach or protect big-billing market leaders from their rivals, as a buoyant legal market and deep-pocketed competitors deal a strong bargaining hand to ambitious lawyers.

At firms such as Allens, Ashurst, Gilbert + Tobin, Herbert Smith Freehills and King & Wood Mallesons, some partners at the very top of the scale are now taking home pay packets close to, and in some cases more than, $5 million.