"A general alert has been sounded across the state with a central control room set up to monitor the flood situation with the rising level of all major rivers leading to floodwaters inundating hundreds of villages," IANS quoted Bhumidhar Barman, Assam revenue, relief and rehabilitation minister, as saying.
IANS said that the Brahmaputra river is flowing above the danger level in at least seven places in Assam.
The Regional Meteorological Center Tuesday warned of more rains and thundershowers in the next 24 hours.
"So far 125 villages have been affected with an estimated 149, 856 people displaced in the first wave of floods to hit the state, " Barman told IANS.
Residents of flood-hit villages in the North Lakhmipur and Karimgang areas were forced out of their homes late Monday and are now sheltered in makeshift tents and on other raised platforms and embankments.
Barman said the flood situation was grim with breaches in embankments reported from some places.
Thousands of villagers have lost their homes and croplands in the floods.
Road transport has also been hit in some parts of the state because highways are flooded.
As one of Asia's largest rivers, the 2,906 km long Brahmaputra traverses China's Tibet region, India and Bangladesh before converging with the Bay of Bengal.
Every year, floods leave a trail of destruction, washing away villages, submerging paddy fields and drowning livestock, besides causing loss of human life and property, in Assam with a population of 26 million.