China has detected 10 cases of radioactive contamination in the country since March 16, an official with the country's quarantine watchdog said on Saturday.

High levels of radiation has been found on people, planes, vessels and containers entering China from Japan, said Li Yuanping, a spokesman for the General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ).

The AQSIQ has ordered local quarantine authorities to intensify radioactive analysis of articles entering the country after radioactive fallout from Japan's crippled nuclear plant, the spokesman said.

A ship, a plane and a batch of imported material were the three latest cases reported to the administration on Friday. They had entered the country through Jiangsu and Zhejiang provinces and were found to have high radioactive levels.

The first radioactive case involved a plane that arrived in Dalian City from Japan on March 16, which returned to Japan on the same day. Other cases involved several ships, containers and two Japanese tourists.

Li Yuanping said that quarantine authorities would continue to closely monitor radioactive levels at China's ports to ensure people's safety.