Parliament is this week expected to debate laws hitting convicts sentenced at the Magistrates Court with a mandatory $50 levy, which jumps to $150 at the Supreme Court.

Criminals will still need to pay an existing victims of crime levy as well as court costs.

Australian Lawyers Alliance state president Henry Pill labelled the levy an unfair tax, describing it is another barrier to accessing justice.

''We are already dealing with people who find themselves in crushing poverty and who are often unemployed,'' he said.

''Slugging them with a 'crime levy' only compounds the problem.''

Courts will not have a choice about whether or not to impose the conviction costs, but child offenders will not have to pay.

Those who fail to pay may have their driver's license or vehicle registration suspended, property seized or sold, or their wages and savings diverted.

The costs cannot be waived or converted to a find or imprisonment.

Attorney-General Vanessa Goodwin has argued criminals deserve to contribute to running the court system, saying similar levies existed in Queensland and New South Wales.

Tasmanian Law Society president Matthew Verney said the payment was simply a tax, and should not be confused with any punishment efforts.

''It is not part of the sentencing process, does not form part of the punishment for offenders that courts impose, and is simply the introduction of a crude user-pays approach to justice in Tasmania,'' he said.

''It is another effort by the government to remove the discrection of the courts in the sentencing process.''