Dementia NZ isn't surprised by the treatment of a 93-year-old man trespassed after an altercation at a Christchurch bank.

BNZ isn't commenting on the details, only saying it has a duty to ensure safety for customers and staff.

Age Concern Canterbury CEO Simon Templeton says they have a health team member helping the man - and it's a work in progress.

"We're still involved and still looking to support him around this issue and any ongoing support he might need. It's a work in progress here."

Dementia NZ CEO Paul Sullivan they're trying to tackle the lack of awareness by customer service people when it comes to the condition.

He says many people don't know it's possible to live in the community and have Dementia.

"They are going and participating in community events. They're going to the bank, they're going to the supermarket, they are doing all this stuff, and it's just not practical to have somebody with a person all the time, and in fact a person may not want someone with them all the time."

Sullivan says there is a tide of dementia coming our way. While there are 60,000 people with the condition currently, that's set to triple by 2050.