National Australia Bank (NAB) planning to reduce its stake in its US subsidiary Great Western Bancorp (GWB) to just over a third.

The Australian lender said it will slash its stake in the US bank from 68.2% to 37.1% through the 18 million share sale.

However, the price for the shares has yet not been determined.

NAB acquired the US lender for nearly A$1bn in 2008 and offloaded a 27.6% stake in October last for $288m.

BofA Merrill Lynch, Deutsche Bank Securities and JP Morgan Securities will act as the joint book-running managers and underwriters for the offering.