ANZ will buy Royal Bank of Scotland's operations in six Asian countries for $US550m (A$687m) in a deal that underlines the ability of Australia's strongly capitalised banks to acquire assets for highly competitive prices from struggling international peers.

ANZ, which wants to generate a fifth of its earnings from Asian operations, will buy RBS's retail, wealth management and commercial businesses in Taiwan, Singapore, Indonesia and Hong Kong, as well as the UK bank's institutional banking businesses in Taiwan, the Philippines and Vietnam.

RBS, which reports first-half results on Friday, has been in talks with ANZ and the UK's Standard Chartered for months over the sale of its sell retail assets in Asia as it tries to shrink its balance sheet. The assets include 170 branches, with 28 in India and 13 in China. StanChart has been interested in acquiring RBS units being sold in China, India and Malaysia.