A demolition company will no longer be working in Christchurch's quake-damaged CBD after Civil Defense withdrew its accreditation.

After receiving information from police, Civil Defense withdrew accreditation for one demolition company and one person attached to another company, Civil Defense national controller Steve Brazier said.

Accreditation is needed for the companies to work in the red zone to clear the debris from February 22's 6.3 magnitude earthquake.

Over 70 demolition companies, mostly from the South Island but also further afield, have been accredited to do the work, Mr Brazier said.

The accreditation process was "robust", and Civil Defense took seriously any suggestion of criminal activity by companies and contractors within the cordoned off central city.

"These systems and protocols will ensure this recovery work is done in a controlled and managed way.

"Civil Defense is working closely with police, who will actively investigate and prosecute any criminal behavior reported to them."

A construction worker and a company director, were arrested last week and were due to appear in Christchurch District Court on May 23.

How could you be so stupid? Nothing like blowing the next couple of years of work for a few hundred bucks of other people's stuff.