Westpac customers will close their accounts and take their business elsewhere if the bank goes ahead and closes five branches across the country, says a workers' union.

Westpac has confirmed its plans to close three Christchurch branches in Sydenham, Lincoln and New Brighton, and one in both Auckland and Wellington in February.

"This is another example of a big Aussie-owned bank abandoning New Zealand communities," First Union's southern region secretary Paul Watson said. 

He says the bank didn't consult with the community before taking action, and now customers have made their voice heard with over 1000 people signing a petition urging Westpac to keep its Lincoln branch open.

"Some Westpac customers in Lincoln are even telling us they're going to take their business elsewhere when their branch closes," Watson said.

Westpac hope to keep banking solutions available in the affected areas, by having an ATM and local digital ambassadors at each branch who can help customers gain confidence with alternative ways of banking in the digital age, says a bank spokeswoman.

The bank confirmed the "majority of affected staff" will be transferred to other branches.

Last year Westpac came under heavy fire from New Zealanders after its decision to close 19 branches across the country.

Westpac's stated reasons for the closures include declining over-the-counter transactions, but staff confirm a steady stream of customers still visit the bank each day, Watson said.

"Yes, more people are doing their banking online, but you still need branches to take out loans, request financial advice and more," he said.

- NZ Newswire