Labour leader Phil Goff is standing by a mailed leaflet telling mothers on a benefit they "won't be around to celebrate" their child's first birthday if National wins the election.
The leaflet, which was sent nationwide, aims to highlight National's welfare reforms, in particular the proposal to work-test sole parents who have more children while on a benefit.
National's welfare reform is proposing a Sole Parent Support. Those receiving it would be expected to work part-time when their child turns 5, and full-time when their child turns 14.
If they had another child while still receiving the benefit, they would have a 12-month exemption from work expectations. After this lapses, they would be expected to return to part-time or full-time work, depending on the age of their youngest child excluding the newborn.
Mr Goff said the leaflet was deliberately hard-hitting.