Treasurer Joe Hockey has suggested the wives of senior government ministers may have kept their husbands in the dark about whether or not they "double-dipped" with their paid parental leave entitlements.

And in an extraordinary interview, Mr Hockey has suggested his own wife doesn't always tell him about their household finances but did not say why.

The Abbott government wants to stop women from accessing the basic 18-week minimum wage taxpayer-funded scheme if they are being paid more generous entitlements by their employers. The change would affect up to 80,000 women.