Police have put extra powers in place to deal with anti-social behaviour after two officers were injured.
Two people were arrested on suspicion of assaulting an emergency worker after the officers were hurt in separate incidents in Cardiff Bay on Friday.
Police have since imposed a 48-hour dispersal order at the Oval Basin, outside the Wales Millennium Centre.
“Violence, disorder and antisocial behaviour will not be tolerated,” said Det Insp Jeff Burton.
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A 27-year-old woman and a 23-year-old man remain in custody.
The extent of the officers’ injuries are not known.
The force said officers were needed to police large crowds at taxi ranks, with a “small number of disputes” and “incidents of violence” also in the area on Friday.
DI Burton said: “A number of coronavirus restrictions remain in place, and it is important that people take personal responsibility and follow them, for their own safety and that of others.
“The vast majority of people did just that, but the selfish actions of a minority left us with no choice but to impose the section 35 dispersal notice for the area.
“And anyone intent on causing trouble or behaving in a way that law-abiding people will find offensive, should stay away or expect to be dealt with by our officers.”
The order gives police the power to exclude a person from an area.
Another 48-hour dispersal order was imposed on the area last month after “unsavoury scenes”, largely said to be alcohol related.