UPDATED 8.31PM All staff members are now accounted for as firefighters battle a large blaze at a business in Christchurch.

Fire Service shift manager Andrew Norris confirmed everyone was accounted for and there were no injuries.​

He said it was not known where the two previously missing employees had been, but they had not been in the burning building.

Norris said no rescue attempts were made, as emergency services had been working to confirm the whereabouts of the two staff.

Firefighters were called to the large blaze at the Tait Technology Centre on Wairakei Rd, Harewood, at 6.15pm.

The building is close to the Harewood Fire Station, and the first truck was there within three minutes.

At its peak, there were 10 fire trucks in attendance.

Newstalk ZB reporter Ben Aulakh, who is at the scene on Wairakei Rd, said there were still seven or eight fire engines on site, and plenty of smoke in the air.

"I just heard one of the fire officers talking to one of his colleagues, and it looks like they're going to be here for most of the night.

"But I think that's just going to be dampening down the building and making sure that everything's safe."

Two people, believed to be cleaners, were in the building at the time the blaze started.

A wide cordon remains in place.