BEIJING - Four more Chinese provinces have been put under a pilot reform program which eliminates life tenures for primary and middle school teachers and raises the threshold of entry to the profession, an official with the Ministry of Education said on Tuesday.

The addition of Shanxi, Anhui, Shandong and Guizhou brings the total number of provinces covered by the program to 10 nationwide, said Xu Tao, director of the ministry's Department of Teacher Education, at a press conference.

"The pilot reform program has raised the standards for teachers' qualification exam and helped to improve their quality," Xu said.

Under the program, all teachers should be subject to the scrutiny of a unified national exam and graduates from teachers' training schools or colleges will no longer be acknowledged straight away as qualified for teaching after graduation.

In addition, life tenures will be scrapped to get rid of under-performing teachers, and teachers have to register every five years to be active practitioners.

Initiated in 2011, the program only covered primary and middle school teachers in the two provinces of Zhejiang and Hubei at its start. Four provincial areas -- Hebei, Shanghai, Henan and Guangxi -- were incorporated into the program in 2012.

The government aims to expand the reform project to all 31 provincial regions in the Chinese mainland by 2015, according to the ministry.

China had about 25 million registered teachers by the end of 2012.