Heavy monsoon rains and mudslides in Sri Lanka have killed at least 26 people, the government said Tuesday, ordering the army to help tens of thousands displaced.

Another 42 people were injured, junior defence minister Premitha Tennakoon told parliament, with 130,000 people forced from their homes by the floods in 23 out of 25 districts across the island nation.

"We have deployed the military to assist the relief operations," Tennakoon said. "Boats have been deployed to help with the supply of relief."

Sri Lanka depends on seasonal monsoon rain for irrigation as well as hydroelectricity, but experts have warned that it faces more frequent floods as the world heats due to climate change.

Sri Lanka's main weather bureau forecast an easing of rains but said the threat of floods had not receded. Low-lying areas remain swamped.

The government had ordered all schools to remain shut on Monday after the weekend holiday, and several in the worst affected southern province remained closed on Tuesday.