Westpac will sack about 300 of its staff in its business and retail banks as part of an ongoing push to reduce its office headcount by 20 per cent.

The affected staff were informed on Thursday, according to the Finance Sector Union, and project delivery and program management workers in the retail and business bank will bear the brunt of the cuts. While hundreds of employees are on the way out, it is a small portion of the bank’s 38,000 staff.