Bollywood megastar Amitabh Bachchan, one of the most effective campaigners against polio, is likely to work for the cause again.

Amitabh, who is goodwill ambassador for UNICEF, says UN officials have asked him to again extend his support to the cause.

"I have worked tirelessly for the eradication of polio in certain distinct parts of our country, namely Bihar and Uttar Pradesh. The UN authorities had come over to meet and discuss how they could extend the appointment further and how we could work together for the benefit of children, " Amitabh posted on his blog www.bigb.bigadda.com Monday night.

Big B has been actively campaigning for polio eradication since 2002 and was officially appointed UNICEF Goodwill Ambassador with focus on HIV/AIDS and polio eradication in April 2005.

The matinee star proved to be the most successful ambassador yet of the drive to eradicate polio, the crippling disease that affects children under five.

A study commissioned by the Health Ministry and UNICEF and conducted by the Social and Rural Research Institute in January this year, found that 73.6 percent guardians with children under the age of five in lower socio-economic categories could recall the television advertisement featuring the star.

His wife Jaya, daughter-in-law Aishwarya Rai and cricket star Sachin Tendulkar have also campaigned with him. But clearly Amitabh is the one who scores in India's vast rural countryside and urban settlements.

India is one of the few countries where polio is still prevalent. The central government is trying hard to get rid of this disease. The number of cases are slowly going down in the country. While 559 cases were reported in 2008, this year so far there have been 464 cases. Out of the total cases, 95 percent are reported in Uttar Pradesh and Bihar.

His movie commitments and other activities keeps him busy, but Big B takes out time to work for the deprived and try to facilitate them with their basic fundamental rights.

He says they also talked about infant mortality rate in the country. According to the health ministry, child mortality rate in India is 56 for 1000 alive births. "It is perhaps highest in our country, " wrote Amitabh.

He also discussed other social issues. "How we could work towards the right of education for those less fortunate, to be able to afford these facilities, or even be a part of a program where literacy was being given due place and position."

The actor, who is preparing for the release of his next "Aladin", is hopeful about the government's initiative on the right to education.

"The Government is in the process of initiating an act through our constitution or through the parliament, where every individual shall possess the right to be educated. This shall be a most laudable initiative, " he wrote.

"Similar actions should be initiated in the field of medical care. There is such a paucity of hospitals and proper medical care in and around us, that one shudders to think what and how the poor or the common man deals with conditions where his health is at stake."