Strongly opposing the Centre's move to make Aadhaar mandatory for opening bank accounts and financial transactions of Rs 50,000 and above, West Bengal Chief Minister Mamata Banerjee on Friday said the poor will be affected by the decision most.

"The poorest of the poor and the marginalised people will be the worst sufferers if Aadhaar is made mandatory unilaterally," Banerjee tweeted.

She added that Aadhar has privacy issues and that the government should not make it compulsory.

"Aadhaar has serious issues about privacy. Govt must not make it mandatory before 100% coverage is achieved," Banerjee wrote in the next tweet.

According to the new mandate, all existing bank account holders will have to submit Aadhaar card numbers to banks by December 31 this year, failing which the accounts will become invalid.