Revenue and Disaster Management Minister Surya Narayan Patro said several rivers were overflowing in Ganjam district.
As more than two lakh people were cut off from the rest of the state, three choppers were pressed into service for relief and rescue operations, Patro told IANS.
Four members of a family, including two minors, died in Jagatsinghpur district after the house in which they were sleeping collapsed Thursday night, special relief commissioner P.K. Mohapatra said.
"The situation is serious. We are asking people to stay on rooftops. We will rescue them," he told reporters.
The government also ordered all schools and colleges in 12 districts closed till Monday.
Apart from Ganjam, the other districts affected by the latest round of rains and floods include Gajapati, Kandhamal, Khurda, Puri, Cuttack, Jagatsinghpur, Kendrapada, Bhadrak, Balasore, Mayurbhanj and Nayagarh.
More rains are expected in the next two days.
The Bhubaneswar-headquartered East Coast Railway said train services remained disrupted between Khurda Road in Odisha and Vijayanagaram in Andhra Pradesh after flood waters submerged rail tracks in some places.
As a result, long distance trains have been diverted.
The heavy rains have also cast a shadow over the One-Day International cricket match between India and Australia to be played at Cuttack's Barabati Stadium Saturday.
About 1.2 crore people in 17 of the state's 30 districts have affected, the government said.
--IANS (Posted on 25-10-2013)