Banks provide the best customer service experiences and telco companies provide the worst, a survey has found.

Seven of the top 10 spots in the online Colmar Brunton survey of 1020 people are taken by banks.

The independent survey rated a good experience on a scale from a 1 (pretty happy) to a 10 (absolutely thrilled) and a bad experience from 1 (felt disappointed) to 10 (full of rage).

A third of New Zealanders had encountered a particularly good banking experience.

One fifth had endured a "particularly bad" telecommunications experience.

Telecommunications companies are frequently the subject of consumers' rage because they often use call centres and the complex technical elements involved in handling problems can mean that issues aren't always resolved quickly.

Dick Brunton, chairman of Colmar Brunton, believes internet banking has helped banks become much more customer-focused and efficient, which led to their high ranking.

Mr Brunton said airlines had also done a great job of conducting business online.

"But businesses should be wary of going down the automation track without considering how it feels to the consumer," he said.

"Telcos are widely criticised for automating their phone systems in a way that is cold, impersonal and actually makes it harder for consumers to interact with them."

Negative customer experiences had decreased from 75 per cent in 2006 when the survey was first conducted to 59 per cent, but Mr Brunton warned bad experiences could be more damaging now because customers had more "ammunition" with social media forums to vent their frustrations.

Customers were twice as likely to tell people about a bad experience than a good one, he said.

"Still, New Zealanders are reasonably forgiving of a problem with customer service, but what really matters to them is how it's handled and resolved."

ASB spokeswoman Catherine McGrath said the bank was "absolutely delighted" to rank as the organisation with the best customer service experiences.