Grandparents will receive the credits from 2011, but only if they care for a child aged under 12 for more than 20 hours a week. Those who reach state pension age on or after 6 April 2010 need to have paid NI contributions over 30 years in order to qualify for a basic state retirement pension.
Currently, only stay-at-home mothers receive help to top up their missing NI contributions.
Sam Smethers, chief executive of Grandparents Plus, said, 'We warmly welcome the introduction of the grandparent NI credit. One in three working families rely on grandparental childcare. We know that working-age grandmothers on low incomes are the ones who are most likely to be providing that childcare, with the risk that they could miss out on a full basic state pension.
'This is also an important victory for the principle that the care grandparents provide does count and should be recognised. We believe this has implications for other areas of Government policy.'
The Chancellor also said Child Tax Credits would increase by an additional £20 a year above indexation from April 2010, and parents could claim Working Tax Credit a month after they start part-time work to help pay for childcare.
He also announced plans to contribute £100 every year to disabled children's Child Trust Funds, with severely disabled children receiving £200 per year to help contribute to their higher financial needs as they enter adulthood.