A deal for Australian banking group NAB to buy the Australian stockbroking and wealth management arm of US banking giant Citi may be imminent, with the retail bank understood to be in the final stages of due diligence, according to the Sydney Morning Herald.

Speculation has intensified that NAB will become the first retail bank in recent times to move back into equities dealing, after previous poor results of banks running brokerages in the country.

The purchase may be sealed within the next few weeks and would see NAB absorb Citi Smith Barney, the retail broking and wealth management arm operated by the largest US bank in Australia.