Ninety students and staff from a language school housed in Canterbury TV (CTV) building in earthquake-ravaged Christchurch, New Zealand, were either missing or unaccounted for.

King's Education Ltd specializes in teaching English to international students.

Of those 58 were "new Monday starters", nine were staff including King's Education managing director Brian Taylor, 10 were from the Toyama Study Group of Japan, while 13 were "other students", according to the institution's website.

About seven Chinese students were also missing, presumed in the building.

Six of the 15 staff at the school had been accounted for, 11 students from Toyama Study Group had been rescued and 16 of the " new Monday starters" were safe.

Many of the rescued students had injuries and were in Christchurch Hospital, with one transferred to Auckland Hospital.

King's Education was opened in 1994 and is one of the top English language providers in New Zealand.

Fifteen CTV staff were also believed to be trapped in the four- storey building, which collapsed after Tuesday's magnitude 6.3 quake, CTV chairman Nick Smith said.

Four Filipino nurses were also believed to be trapped under the rubble.

Searchers were still looking for survivors in the devastated CTV and Pyne Gould Corporation buildings.

The official death toll on Wednesday night stood at 75, but leaked official documents broadcast by media suggested authorities feared it could surpass 300 to become New Zealand's worst natural disaster.