According to AFP, a rain-flooded river has deluged the Kaziranga National Park in remote Assam state, home to the largest concentration of the world's remaining one-horned rhinoceros.
"More than half of the Kaziranga National Park is under water. Animals are migrating from the sanctuary to adjoining hills for safety," Assam forest and wildlife minister Etuwah Munda told AFP.
"We are taking all precautionary measures and I myself will be camping in the park to monitor the situation."
The park, spread over 450 square km is prone to flooding during the annual monsoon rains.
Some 14 rhinos and hundreds of other animals died during floods in 2012, many of them mown down on a nearby highway by speeding vehicles as they left the park for higher ground.
Park officials have this year taken precautions, including erecting barricades along sections of the highway.
"Forest guards are asking drivers to drive under 40 kilometres (25 miles) an hour as the animals use the highway to cross over to the hill to escape the floods," the minister said.
A recent census estimated there were 2,400 one-horned rhinos in the park out of a global population of around 3,300.
Park officials are worried about poachers targeting them and other animals as they leave the sanctuary for the hills.
"Poachers have a tendency to target animals by taking advantage of the floods. We have put forest guards on alert in the hills where the animals take refuge," Munda said.
Kaziranga has fought a sustained battle against rhino poachers who kill the animals for their horns, which fetch huge prices in some Asian countries where they are deemed to have aphrodisiac qualities.
Floods have claimed 14 lives, submerged up to 1,200 villages and displaced more than 800,000 people across Assam in recent weeks, a state government statement said Tuesday.