China will establish a national groundwater monitoring system during the next five years to prevent excessive exploitation, a government official said on Monday.

The system will include more than 20,000 monitoring stations across the country, according to Yan Yong, an official with the Department of Water Resources under the Ministry of Water Resources.

The move is aimed at countering the overuse of groundwater that is now rife in more than 300,000 square kilometers of Chinese territory. In some areas in North China, where water shortages are most severe, groundwater still accounts for more than 70 percent of the water supply, the ministry said in a guideline in August.

"We cannot wait for problems to take place and then try to rectify them," he said during a news conference before World Water Day on March 22.

The authorities will also explore using the system to ration groundwater, he said.

Yan explained that the monitoring system will enable the authorities to identify areas in a timely way where overuse is taking place and act quickly to prevent it.

More than 17 billion cubic meters of water that should be left in the ground are being taken from underground sources each year, according to the ministry.

"The problems that come along with the over-extraction are virtually impossible to rectify," he said, adding that ground subsidence as deep as two meters had hit some areas because of the abuse of water resources.

In Hebei province, where groundwater overuse is most serious, the central government has launched a restoration program that devotes more than 7 billion yuan ($1.07 billion) each year to cope with groundwater overuse and restoring water levels.

Yan said a key step in that program is to reduce water consumption in the agricultural sector.

Groundwater in the province has also been rationed to each individual user in different sectors, he said.

However, the groundwater level in the province has only been restored by a small margin and progress has been minor, he said.

Wang Zhi, deputy head of the Department of Policies, Laws and Regulations at the ministry, said it is still working to draft a new regulation on the use and protection of groundwater.