A survey of bank workers has found high levels of workplace bullying, says the financial workers union, Finsec.

Finsec national organiser Matthew Fitzsimons said the survey, which looked at the Westpac and National banks, found that 43 per cent of workers said they had been bullied.

Just over half of those workers who had experienced bullying suffered it on a weekly basis, he said.

"We are talking about things like put downs in front of customers and colleagues, aggressive language, threats that they will lose their jobs and being isolated and ostracised," he told NZPA.

Mr Fitzsimons said the survey, which would eventually cover all the five main banks, arose from work the union did last year looking at high workloads.

He said both Westpac and National had zero tolerance policies on bullying in the workplace, but workload and performance pressures were undermining that.

"There are five very, very competitive banks in New Zealand and they see a big threat from new players in the market and it's the staff who are bearing the brunt," he said.

"These banks have actually done some quite good work in this area (of bullying) but it's the staff levels and workload which is running counter to that."

He said the aim of the survey was to gauge what was taking place and hopefully to help spark a culture change in the banks' systems.

"We definitely see this as a systemic problem rather than being about individual people."

The survey was of 364 workers at Westpac and 143 at the National Bank.

Westpac spokesman Paul Gregory told NZPA the bank took the issue of workplace bullying extremely seriously and as a result had a code of conduct policy and harassment prevention policy.

He said a comprehensive independent anonymous survey conducted for the bank found that 74 per cent of workers believed they had positive working relationships, 72 per cent believed their immediate manager did a good job, and 77 per cent said employees were treated with respect.

The survey was of 4205 staff, he said.

"We are getting a slightly different message than from them (Finsec) but it is still something important and we'll always take it seriously."

Mr Gregory said the bank had asked the union to encourage workers with problems to use the processes set out in its conduct and harassment policies.

A National Bank spokeswoman said the company had scored the highest level of worker satisfaction among the five main banks in another industry survey.

It took workplace bullying extremely seriously, but questioned the reliability of the Finsec survey given its extremely small sample size, she said.