The group had also been to a Night 'n Day store.
The 18-year-old had previously been spoken to about breaching lockdown and was issued an infringement.
The four passengers were given a warning, Dinnissen said.
In a separate incident, a car and motorcycle were seen ripping up the Montecillo Sports Ground at 1pm on Wednesday.
Police followed muddy tyre tracks back to an address on Glen Rd address and issued the owner of the car an infringement for a breach of lockdown and for the manner of driving.
The car was impounded and the city council would be contacted about the issue, he said.
Dinnissen also stressed the need for exercise to be done locally.
People should not be driving long distances to cycle, he said.
He brought up an example of cyclists travelling from Green Island to Bayfield and then riding 20km out to Portobello.
Although the rules were ''a bit murky'', the behaviour was unacceptable.
Cyclists "aren't liked by many" and those flouting the lockdown rules gave them a bad name, he said.