Superannuitants living on their own in Canterbury are asked to contact Work & Income to let the agency know they are safe.
Social Development Minister Paula Bennett says about 18,000 elderly people are known to be living alone in the Canterbury region.
Work & Income personnel have managed to get in touch with about 11,000 of them, but have not been able to make contact with many more.
Mr Bennett says calls are continuing to come in to the Government's helpline from people needing advice and assistance.
She says demand for emergency welfare payments is increasing, with people who have had to leave their homes, needing food and clothing.
Aged care residents to move to new homes
Almost 200 residents from aged care facilities are to be relocated because of structural damage and water-supply problems.
Canterbury District Health Board says the residents will be moved from Wednesday onwards. Most are expected to be rehoused by the end of the week.
Chief executive David Meates says they have been safe and well looked after since the quake on Saturday, but the situation is unsustainable.