'Akshay Kumar has decided to adopt a village for rehabilitation,' Jha told reporters here.
Jha, who is from Bihar, has set up an organisation called Punarwaas with help from NGOs like Anubhooti and Prayas.
He said he was running a relief camp for 5,000 people in Kataiya in Supaul district, one of the worst hit by the floods. He said he had the backing of several Bollywood friends.
Apart from adopting a village, Akshay has donated Rs.2.5 million to Jha's rehabilitation programme.
'Akshay promised that he would provide more money if required,' said the director, who has made films like 'Apaharan' and 'GangaaJal'.
Disaster Management Minister Nitish Mishra said that rehabilitating hundreds of thousands of people affected by the calamity was a 'Herculean task'.
'The state government plans to adopt the rehabilitation pattern used for victims of tsunami (2004) as well as the earthquake in Gujarat (2001),' he said.
It has been a month since the Kosi river breached an embankment in upstream Nepal, swamping hundreds of villages and affecting over three million people in Bihar.
The disaster has claimed at least 50 lives, according to official estimates, but voluntary agencies fear the toll could be in thousands once the water recedes and bodies are recovered.
About 989,000 people have been evacuated to safer places. Around 350,000 people have taken shelter in over 300 relief camps.