Changes to the law on trespass, which is currently a civil offence, were signalled in the party’s general election manifesto, which pledged: “We will tackle unauthorised traveller camps.”
The document outlines plans to give police new powers to arrest and seize “the property and vehicles of trespassers who set up unauthorised encampments, in order to protect our communities”.
It could be the biggest crackdown on Gypsies and travellers by any government.
Opponents of illegal fox-hunting claim the measure would also be a backdoor way for the Tories to protect the practice, by criminalising hunt monitors and saboteurs, leaving them open to prosecution.
Fox hunting opponents say the party has not had enough MPs in the Commons that support it to overturn the ban so targeting activists is a “sneaky” way of allowing meets to continue uninterrupted.
A spokeswoman for the National Federation of Gypsy Liaison Groups said: “To target a tiny part of the population in this way (that happen to be a minority) is just plain wrong and totally unnecessary. It appears to be racist.
“Increased police powers (which the police neither need nor want) would, in effect criminalise the gypsy and traveller way of life.”
The government last year launched a consultation on unauthorised encampments, including clamping down on trespass.
Police chiefs and police and crime commissioners said the lack of sufficient accommodation for Gypsies and travellers was the main cause of unauthorised encampments.
The federation spokeswoman said criminalising trespass would be likely to breach the Human Rights Act and the Equality Act, traumatise children and consume resources on rehousing and supporting families taken off the road.
However, one lawyer told The Independent he could not see any prospect of an argument under either Act having any chance of success.
Separately, animal protection supporters have also slated the trespass crackdown, accusing the Conservatives of appeasing hunt supporters.
Penny Little, a monitor of the Grafton Hunt in Northamptonshire and founder of a wildlife rescue centre in Oxfordshire, said: “They [the Conservatives] are sneaking in a move that could leave illegal hunting completely unscrutinised, and allow it to continue without even the present, very slight, risk of prosecution.
“There are many monitor and [sabotage] Facebook pages that show the reality of what is happening every day in our countryside. The violence, obstruction and intimidation meted out by hunts and their supporters can clearly be seen, as well as multiple examples of foxes, deer and hares being illegally hunted.
“Hunt sabs trespass when necessary to save hunted animals from the hounds. What sort of political party would make it their business to protect criminal animal abusers from the cameras, leaving the illegally hunted animals to suffer the worst the hunts can inflict upon them?
“If anyone believes the Tory party has admitted defeat on helping hunters, they are wrong.”
Guy Shrubsole, of Friends of the Earth, also highlighted a previous Conservative promise to protect the right to roam over land, which was passed in law in 2000. But landowners said the new move could lead to more poachers being arrested.
The Conservative party has been contacted for its response and asked how criminalising trespass would sit with the right to roam.