Firefighters are battling a major blaze in the Christchurch suburb of Hornby.
Emergency services and police rushed to the Brixton Rd property, believed to be a former community hall or Masonic Lodge, just before 11am after a series of explosions were heard.
Police southern communication spokesman Trevor Cross was unable to confirm reports that a methamphetamine lab was involved.
Police and CIB officers from the suburban Hornby station were attending, but mainly to control traffic in the area, Mr Cross said.
A Fire Service communications centre spokesman said six fire engines, a command unit and a hazards unit were at the scene.
A large structure at the address was "well involved," he said.
Callers had indicated there had been a number of explosions as the fire broke out.
The Fire Service communications supervisor said the hazards unit was on site in case firefighters needed to be decontaminated.
"All we're doing is taking precautions," he said.
Police hadn't advised firefighters that a drugs laboratory might be involved, he said.