Two South Korean students have gone missing in Christchurch, New Zealand, which was hit by a six-point-three magnitude earthquake on Monday morning, local time.

A Foreign Ministry official said Wednesday that the South Korean Embassy in New Zealand received a report about the two missing students who are in their early 20s. The two are presumed to be brother and sister.

The official said the building which houses the language institute where the missing students were studying was destroyed by the earthquake, and that the two students are presumed to be buried under the debris.

The official said the ministry is seeking to confirm whether there are any other missing Korean students as five to six more Koreans were found to be studying in the building at the time the tremor hit.

Around 150 to 200 people were buried under the debris when the building crumbled. Some 100 of them have reportedly been rescued.

The official said the South Korean Embassy in New Zealand dispatched a consul to the site of the collapsed building to assess the situation.