An extra $1.5 billion is needed in increased social security payments, mostly for the unemployed and new migrants, Director of Social Welfare Andrew Leung Kin-pong says.
Mr Leung said his department would apply for the extra money from the Legislative Council finance committee at the end of the year.
The Comprehensive Social Security Assistance (CSSA) scheme was allocated $11.5 billion in April for the current financial year.
Mr Leung said the extra funds were needed mainly as a result of rising unemployment.
'It can be understood that it must be very difficult for newcomers from the mainland to find jobs in the economic slump,' he said.
Last month, the number of jobless people on benefits jumped 55.5 per cent to 25,116, compared to 16,152 in the same period last year. At the same time, 20,100 new migrants were on the dole. No previous figures were kept.