United Future leader Peter Dunne is calling for the Office of the Children's Commissioner to be merged into the Families Commission.
The party championed the establishment of the Families Commission under the previous Labour-led government.
Mr Dunne says much of what the agencies do overlap, is inter-related and they already share administration services.
He says a full merger is the obvious next step and that would create more of a one-stop shop for parents and families to seek advice from.
The minister says his comments are not a slight on the new part-time Children's Commissioner, Dr Russell Wills.