The Odisha government on Friday put the coastal districts on high alert as the low-pressure area intensified into a depression, causing heavy rainfall in several parts of the state, a senior official said.

"As a fresh spell of rain could further worsen the flood situation in the Mahanadi basin area, the state government has asked the district administrations to provide assistance to the people in the affected areas," Special Relief Commissioner PK Jena said.

"Under the impact of the depression, a third in the fortnight, heavy rains triggered a flood in Jagatsinghpur and Rayagada districts, and some areas in Subarnarekha basin in the northern region," a revenue department official said.

Jagatsinghpur district recorded 107 mm of overnight rainfall, as per the weather department.

"The low-pressure area over northeast and adjoining areas of east-central Bay of Bengal moved northwestwards and concentrated into a depression, centred about 310 km east-southeast of Balasore," it said.

It is very likely to intensify into a deep depression and is likely to cross West Bengal and Odisha coast between Balasore and Sagar Islands in the evening, the weather department added.

It would continue to move west-northwestwards across Odisha, West Bengal and Jharkhand, and move towards north Chhattisgarh and weaken gradually.

In view of the forecast, the Odisha government asked the districts to closely monitor the situation.

A red alert of extremely heavy rain has been issued for parts of Keonjhar, Balasore, Bhadrak and Mayurbhanj districts.

The rains may cause water levels in rivers to rise, flash floods, landslides or mudslides in vulnerable hilly areas and cause damage to susceptible roads and houses, officials said.

An orange alert has been issued for 12 districts, including Kendrapada, Jagatsinghpur, Cuttack, Dhenkanal and Angul. Yellow warning has been issued for Jharsuguda, Bargarh, Kalahandi, Kandhamal, Ganjam, Nayagarh, Khurdha, and Puri.

Fisherfolks have been warned not to venture into the sea till Saturday.

The state government said that the water level in the Hirakud reservoir was at 622.37 feet at 8 am against the full capacity of 630 feet.

"We are creating more space in the Hirakud reservoir and keep the water level within 622 feet as a heavy rainfall is likely to occur in the upper catchment areas of Mahanadi river in Chhattisgarh," said BK Mishra, the chief engineer of the water resources department.

Mishra said that while 2.94 lakh cusec of water was entering the reservoir, 4.76 lakh cusec of water was being discharged downstream.

Efforts are on to maintain the water level within 8 lakh cusec at Mundali barrage near Cuttack, he said, adding that steps are being taken to regulate flood in Subarnarekha and Budhabalang rivers in north Odisha.

The special relief commissioner said that four more gates of the Hirakud dam have been closed, while 24 gates are open.

The ongoing flood has affected over 5 lakh people in 13 districts. As many as 90,000 people were moved till Thursday to 190 relief camps.