Four men have been arrested by police in Wiltshire in what are believed to be the first arrests under the new hunting legislation.
The men were found on an unclassified road near Malmesbury, with four dogs and the carcass of a hare.
A 53-year-old from Ireland and three men, aged 31, 32 and 33, from South Wales, were arrested on suspicion of hunting with dogs.
The four have now been released on police bail pending further inquiries.
The men, who were arrested at 0400 GMT, are also being investigated over possible firearms offences relating to a modified air rifle and possible offensive weapons charges.
Wiltshire Police spokesman Dave Taylor said: "We would stress that they were nothing to do with any of the organised hunts."
In total it is believed more than 270 hunt groups set out on Saturday, just one day after the ban came in.
Anti-hunt groups - such as the League Against Cruel Sports - deployed 100 monitors at hunt meets to check for illegal activity.
Mike Hobday, from the league, said video evidence of the law being broken was to be passed onto police.
"Our evidence suggests that most hunts did operate within the law, many meeting and promptly going home and others peacefully exercising their hounds or drag hunting.
"However, we have received reports of what we believe is clearly illegal activity by a number of hunts across Britain."
The Countryside Alliance said the meets would show the new law was "impossibly difficult to determine" and open to different interpretations.
Chief executive Simon Hart said: "There has been hunting in England for 700 years. This [ban] may take two or three years, perhaps two or three months, to unpick.
"It will be nothing more than a temporary break in normal service."