The Fair Work Commission in late October found Westpac acted unlawfully in knocking back the woman's request to work from home, a move the sector's union said highlighted that flexible arrangements were a legal right.
The Finance Sector Union has written to Australia's bank bosses to ask they review their work-from-home policies, reminding them they could be breaking the law by rejecting requests without proper justification.
"Westpac broke the law when it ignored its own worker's rights and we're putting every other bank on notice that they can't do the same," the union's national assistant secretary Nicole McPherson said on Thursday.
"Our members have proven they can deliver from home … flexibility is not a perk, it's a legal right and we'll keep fighting to make sure every worker in finance can exercise it."
The commission heard Karlene Chandler asked Westpac if she could work from home so she could care for her two six-year-old children, including taking them to and from school.
Westpac knocked that back, along with a separate offer for Ms Chandler to work from a local bank branch in Bowral for two days a week, rather than the corporate office in Sydney.
The commission found the big-four bank didn't respond to her request within 21 days, failed to genuinely engage with her and did not provide specific reasoning behind the decision.
Westpac chief executive Anthony Miller defended the bank's policies earlier in the week, telling investors the firm had one of the most flexible work-from-home policies in the marketplace.
But Ms McPherson labelled the banks "hypocrites" for cutting jobs and offshoring work while simultaneously demanding workers be physically in their offices.
The union wants written confirmation from each employer acknowledging their flexible work obligations.
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