Roxy Tahuparae, of the Hastings Community Patrollers City Assist team, spotted the male stumbling back to his motor vehicle from Subway and called police immediately.
"Police reviewed CCTV footage of the man driving through town and it's a miracle he even made it without causing harm, given the fact that he had driven into the oncoming lane a number of times," he said.
Hastings District Council said incidents like this show the value the "hard-working" City Assist team do to keep the district safe.
"Since City Assist was introduced in 2013, the team members have been walking the city streets seven days a week in Hastings city - and in Flaxmere since 2016 - providing friendly reassurance to retailers and the public that there are people out and about every day who are there to help them if need be," a HDC spokeswoman said.
She said their work includes working closely with police and other agencies.
"Their efforts were also recognised by police last year at a special ceremony held in the Hastings District Council chambers," she said.
Police said the incident was a friendly reminder to the community to call 111 and report this type of driving behaviour.