Police have visited almost 3,700 shops in Northern Ireland since wearing face coverings became compulsory.
Since the introduction of the regulation in August, there has been confusion over enforcement.
PSNI Ass Ch Con Alan Todd said shop visits took place to support retailers, who he added had a part to play to ensure customers comply with the regulations.
Police previously confirmed no fines had yet been issued relating to masks.
Mr Todd told a meeting of the Policing Board: "No fines does not mean no action."
"I'm not saying it's all their job, but there is a role," he said, referring to retailers.
It became compulsory to wear a face covering in enclosed public spaces on Monday 10 August.
The Department of Health said breaches could lead to a fixed penalty notice of £60, reduced to £30 if paid within 14 days.
'Not necessarily for policing'
PSNI Ch Con Simon Byrne added he did "not necessarily see this [area] as a place for policing".
The PSNI said it had received eight complaints related to face masks in shops and there seemed to be 90% compliance with the law.
It said a top priority was targeting house parties.
Around 450 fines have been issued to people found to be attending them.
"This is an on-going daily priority," said ACC Todd.
Police previously said not wearing a face covering in a shop was not an "arrestable offence", but that fines could be issued.
"We will continue to support compliance with the government regulations by engaging, explaining and encouraging people to make the right choices and this includes the mandatory wearing of face coverings in stores," said the PSNI.
"We will only enforce where necessary."