Hundreds of hunt members across the South are to gather in protest on Saturday at the new fox hunting ban.
Some hunts will shoot foxes instead of setting dogs on them
About 30 hunts are meeting in Hampshire, Dorset, Oxfordshire and Berkshire and the Isle of Wight.
The Bicester with Whaddon Chase and the Hampshire Hunt are among many planning to shoot foxes instead of letting dogs kill them - legal under the new law.
Police say they will monitor the hunts, while some anti-hunting activists are planning to disrupt them.
Sara Rutherford, a Countryside Alliance spokesperson who will be riding with the Hampshire Hunt, told BBC News: "You'll find extreme anger that this putrid piece of legislation is being allowed to come into force.
"The law is full of flaws. There are a number of ways in which quarry can still be killed.
"I feel sorry for the fox in this situation - we will see more killed in the UK because they will be shot instead of hunted with hounds.
"A healthy fox can outrun a pack of hounds but it can't outrun a bullet."
Nathan Brown, from the Southern Anti Bloodsports League (SABS), told BBC News: "We are going to have people out at hunts across the South.
"We don't know how many yet, as some people are fearful because of recent violence at anti-hunt protests.
"We're going to be carrying out covert surveillance and if the hunts transgress the law we will make that information available to the police.
"We will also be carrying out our normal activities to try to stop the hunts, including spraying citronella oil from garden misters, to put the hounds off the scent of the fox."
In the village of Burley, Hampshire, members of both the New Forest Hunt and the New Forest Beagles are to stage a rally in the high street instead of a hunt.
Organisers expect 300 foot followers and between 150 and 200 riders in full dress.
Graham Ferris, joint secretary of the New Forest Hunt, told BBC News: "Our rally has two purposes - to help keep up our supporters' spirits on the first day of the ban and to demonstrate to everybody else that we aren't going away.
"We are here for the long term and the ban is eventually going to be repealed or the government changed."
Another anti-hunting activist, Lorna Marcham, told BBC News she would be aiming to sabotage hunts in Berkshire or Hampshire.
"We don't know if the hunts are going to obey the ban and we are going to make sure they do.
"If it is a hunt following a false trail, we're quite happy with that. But if they get hold of a fox, we'll blow our own horns to put the hounds off and crack whips in front of them, as they have been trained to stop when that happens."
Meanwhile, the League Against Cruel Sports said it was not planning counter-protests, both because of recent violence and the fact the ban had now become law.
A Thames Valley Police spokesman said: "Small teams of foot officers will be dedicated to each of the hunts.
"It is not a force priority, although we are there to enforce the Act and investigate any alleged breach of it."