West Midlands Police say the majority of the fines were given to people at house parties, while large gatherings at weddings have also been reported as well as birthday parties.
It came as concerns were raised over funerals taking place in parts of the region with up to 200 people.
New powers enabling police to hand out fines of £800 to illegal gatherings of more than 15 people started last week. The penalties – which supersede the old £200 fines – doubles for each offence up to a total of £6,400.
Speaking at the region's weekly coronavirus briefing, West Midlands Police and Crime Commissioner David Jamieson, said: "The main offenders have been people who have been holding house parties.
"We are also aware that some weddings have taken place which have, flagrantly I'm afraid, broken those Covid rules.
"The vast majority of people are compliant, but I would say to those who are not compliant, that we have already had about 50 of the larger £800 fines that came in earlier this week.
"The police will take action if it's required against those people who are putting their own and other people's lives at risk."
He added that a number of birthday parties had also broken the rules.
Meanwhile Walsall Council leader Mike Bird said funerals had taken place in the borough where up to 200 guests had been present.
"The funerals were reported to the council's enforcement team and there has been police involvement," he said.
"We have a model now that if there is over 30 people present the police are informed, and if there are excess numbers they do attend and make sure those people are advised of the law.
"We are now doing an exercise in improving our communication with funeral directors to make sure that they understand the fine can be levied to them."
Mr Bird said the last recorded incidents were in November and that he hoped the message was "getting through".
"There are some faith groups who have a gathering before a funeral, and that in itself is another danger that we are looking in to," he added.