National is signalling that welfare benefits will be cut by as much as 50 per cent if parents do not meet "social obligations" it is imposing.

If parents on the domestic purposes benefit don't enrol their children in a pre-school and get them regular health checks they will lose as much as half their benefit.

"We will be introducing social obligations, so they will have to enrol their child in early childhood education and get well checks at the doctor by enrolling the local public health organisation," Social Development Minister Paula Bennett told TV3 on Saturday.

In a first round of welfare reforms, the government passed legislation requiring sole parents receiving welfare benefits to be available for work. The obligations outlined on Saturday are a next step.

"If you have kids, then you will lose 50 per cent of your benefit," says Ms Bennett. That's the worst-case scenario. We hope it doesn't get to that," she said.