A Christchurch pensioner was left bruised and badly shaken after an assault outside a city dairy.

St Albans man Jim Bruning, 69, was getting off his mobility scooter to go into a Bealey Ave dairy when a man approached him and demanded money about 7.40pm on Monday.

"This guy said 'I want some money'. I said 'I haven't got any sorry'."

The man then shoved Bruning, causing him to hit the security bars on the dairy's front window.

"It was a bit of a shock actually. I couldn't get up."

Bruning was helped by two customers, with one helping him put the seat of his scooter back on after his attacker ripped it off.

It took him about five minutes "to get my wind back", before he could ride his scooter home, he said.

Bruning told The Press the offender turned up at his house twice yesterday, but he did not open the door, as advised by police.

Bruning said he was unable to sleep after the assault, and felt "terrible" yesterday.

The incident left him with bruising on his back and left shoulder.

"I'm very wary about people now. He wants to be bloody locked up and the key chucked away. To do that to a person who's disabled and on a scooter, [he] is a bloody coward as far as I'm concerned."

Constable Kurt Davison, of Christchurch central police, said the offender was "apparently pretty drunk" at the time of the incident. The incident happened on Bealey Ave, between Geraldine St and Champion St.

Police had spoken to witnesses at the scene, but anyone who believed they knew the identity of the attacker should contact police, he said.

The man was described as Maori, about 173 centimetres tall and was wearing a black hoodie with a white stripe and dark pants.

Anyone with information should contact police on 03 363 7400, or to give information anonymously should call Crimestoppers on 0800 555 111.

- © Fairfax NZ News