Thai authorities are rushing to drill thousands of wells across the country to ensure enough water for drinking and washing, as farmers grapple with a drought and a months-long water shortage.

Authorities examined the water supply and demand nationwide and decided to drill 4,300 more wells, said Suphot Tovichakchaikul, secretary of the National Water Board, which comprises water officials and is chaired by the prime minister.

"We are focusing first on water for consumption and daily use - for drinking, bathing and washing. We have asked farmers for their cooperation to not yet use water for irrigation," said Suphot, who is also chief of the Department of Water Resources.

"We estimate that the end of this year's dry season is May 30. The water we have now has to last for the next four months," he said on Tuesday.

The government will divert a $96m budget from the Department of Groundwater Resources - originally set aside to dig 6,000 wells at temples, schools and farms - for the urgent construction of the 4,300 wells.

The Thai government told farmers last year to limit their water use and grow alternative crops. The cabinet also approved a multimillion-dollar budget in October to help farmers to cope with the drought.

Long-term strategy

Since October, 1,250 wells have been drilled. They are usually dug to a depth of 80 to 100 metres but some wells in Isaan, the agricultural heartland in northeast Thailand, are dug about 300m deep.

Suphot said that the government's long-term strategy includes filling the country's existing dams to capacity by tapping into rivers including the Yuam and Salween along its border with Myanmar.

"These are international rivers, so apart from an environmental impact assessment and feasibility studies, the Ministry of Foreign Affairs will have to tend this issue with respect to relations with neighbouring countries," he said.

Worsening drought could prove another headache for Thailand's military government, which took power after a 2014 coup and is grappling with a lacklustre economy.