"Possibly there'd be around 20 or 30 involved that we're aware of at the moment.
"It's almost ongoing, there's always some restructuring. At the moment for us it's nothing out of the ordinary, but it is on the other hand very concerning that we hear rumours about something a lot bigger."
Westpac spokesman Chris Mirams said some restructuring was currently underway, but denied it was major.
Westpac recently combined its business bank with its corporate and institutional distribution units, he said.
"Following on, we are now looking at strengthening our capability and reducing duplication.
"It's an on-going process to ensure our resources are focused in the right areas to support our customer facing staff effectively.
"Any final figure regarding jobs is expected to be less than three figures."