All schools and colleges across coastal Karnataka's Dakshina Kannada district will remain shut on Wednesday and Thursday as heavy rains disrupt normal life, said an official.

"We have advised all state-run and private schools and colleges across the district to remain closed for two days as a safety measure due to heavy rains flooding roads and localities in the district," Deputy Commissioner Sasikant Sentil told reporters here, about 350km from state capital Bengaluru.

A record 40mm rainfall on Tuesday in the port city of Manganluru inundated several areas, including roads and housing colonies and commercial hubs due to storm-water drains overflowing and garbage blocking their movement.

"Though the south-west monsoon is set to enter the state in the next two days, a cyclonic storm, low pressure and strong surface winds have brought moderate to heavy rains in the coastal areas since Monday," a weather official said.

Forecasting rain or thundershowers over the next two days in the coastal districts and south interior areas due to favouring conditions, the official said fishermen have been advised not to venture into the Arabian Sea and tourists were told to stay away from beaches facing high tides.

"Took stock of the situation in Dakshina Kannada due to heavy rains since Tuesday across the coastal district and directed the administration to take assistance of the coast guard to prevent loss of life and mitigate hardship," tweeted state Chief Minister H.D. Kumaraswamy from Bengaluru.

Pre-monsoon rains were also reported from Udupi, Honnavar, Agumbe, Karwar in the coastal region, Belagavi, Hubballi-Dharwad and Gadag, affecting movement of people and goods and causing damage to crops.