BEIJING - Twenty Chinese students at an English language school in Christchurch are missing following the massive tremor, Beijing says.

A number of Chinese nationals are believed to have been in class on Tuesday when the shallow 6.3 magnitude quake struck, flattening the CTV building that housed the school, China Central Television reported on its website.

Some of those students have not responded to frantic calls or text messages sent by their relatives, CCTV said, adding police believed some of the students may have been sent to hospital.

"With respect to the reports of trapped Chinese students there, we are very concerned and our embassy in New Zealand is quickly checking the situation," foreign ministry spokesman Ma Zhaoxu told reporters on Thursday.

"We have urged the New Zealand side to rescue the Chinese students there," Ma said, without giving a figure for the number missing.

China has dispatched a rescue team to New Zealand to help in the search efforts, Ma said.

The official death stands at 98 tonight, with police holding grave fears for a further 226 missing.

Rescuers have ruled out anyone being found alive at the collapsed CTV building, which housed a TV station and the busy language school for foreign students, and where as many as 120 people may have perished.

CTV said today a total of 32 Chinese students were registered at the school.

Chinese media earlier reported that one of the trapped students had called her husband in China's Guangdong province after Tuesday's quake.

Ninety students and staff from King's Education are either missing or unaccounted for.

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

The school specialises in teaching English to international students.

Fifteen CTV staff and four Filipino nurses are also believed to be among those inside.