A criminal defence lawyer isn't sure changing trespassing laws will significantly impact retail crime. 

The Justice Minister's latest law and order proposal would double maximum fines for trespassing on businesses. 

It will also let owners ban people from multiple sites - and for longer. 

John Munro says the move, alongside an earlier announcement on harsher moves against shoplifting, won't make much difference.

"Most of those sorts of people, I would think, don't have much money in the first place to end up paying a fine - does it really deter them?"

LISTEN ABOVE

• 'Enough is enough': Government beefing up trespass laws, doubling fines
• Govt announces new fines, longer prison sentences for shoplifters
• Luxon fronts as Govt promotes sentencing crackdown
• Govt aims to send a "clear message" with theft, coward punch announcements
• 'We want to send a stronger signal': Minister Paul Goldsmith on the Government targeting 'coward punches'