Leslie Morphy, from the homeless charity Crisis, said most squatters were often homeless and vulnerable, unlike the high profile cases which hit the headlines.
She added: "I think we have brought in something rather draconian to address a small problem, whereas there's a much bigger problem of homelessness generally that we should be addressing."
Crispin Blunt, Minister for Prisons and Probation, said the existing laws on squatting were too complicated. He added: "If you are illegally, knowingly, or ought to know, in improper possession of someone else's house, it's an offence."
Two squatters have responded to immigration officer Julia High - who has said that squatters have no right to move into somebody's home.
Immigration officer Julia High has told Daybreak of her distress after she returned home after a weekend away to discover a group of squatters living in her house.
Squatters will face up to six months in prison and so-called squatters' rights scrapped as it becomes a criminal offence in England and Wales tomorrow. Daybreak's Nick Dixon reports.
- The Ministry of Justice thinks there could be anything from 12,000 to 50,000 people squatting in the UK.
- In 2011 there were 790 trespass or possession orders granted by the courts.
- The MOJ estimates that under the new legislation (when squatting becomes a criminal offence) between 350 to 2,000 people a year will be prosecuted.
- If convicted of squatting they may face a prison sentence of up to 6 months or a maximum fine of £5,000.
- The MOJ also has funds of £160 million to try and get 10,700 empty homes back into use - so that theyre not vulnerable to squatters.
- Legislation applies to England and Wales only.
Campaigners have warned that criminalising squatting in residential buildings would lead to an increase in some of the most vulnerable homeless people sleeping rough.
The introduction of the offence - which will carry a maximum sentence of up to six months in jail for persistent offenders, a £5,000 fine or both - follows a Government consultation on the issue last summer.
But homeless charity Crisis said the new law would criminalise vulnerable people, leaving them in prison or facing a fine they cannot pay.