Starting Jan. 1, contractors working in Philadelphia will have to prove they have paid their city taxes and have the appropriate insurance, or they will not be issued the necessary work permits.

The change grew out of moves Mayor Nutter announced this summer to expand the city's oversight of contractors after the Market Street building collapse that killed six people.

"That's always the goal, to increase oversight and just make sure everyone is playing by the rules," Rebecca Swanson, spokeswoman for the Department of Licenses and Inspections, said Monday.

The changes put the onus on contractors to show they are running reputable businesses before permits are issued, Swanson said. They were not part of the effort Nutter announced this summer, but an internal move made at L&I.

Now, contractors are required to prove they are not tax-delinquent only when they seek to renew their licenses every three years, or if bidding on city work.

Griffin Campbell, the contractor who was charged with six counts of third-degree murder in the June 5 building collapse at 22d and Market Streets, was denied a license last year because he owed back taxes.

He was granted a license after agreeing to enroll in payment plans, city officials said, but stopped making payments when he declared bankruptcy in March.

Campbell's insurance company also said that he lied on documents about the scope of the demolition and that his policy was canceled before the collapse because he had not made his payments.

After the collapse, Nutter announced a series of changes to require better inspections of demolition sites and quicker action to shut down dangerous work.

City Council also is working on a package of bills to change the city's regulation of demolition and construction sites.