The Morrison government’s proposal for a national register that would make public the names, faces and postcodes of paedophiles and other sex offenders has met scepticism from the states, with the NSW government expressing "preliminary concerns".

Some child protection advocates and experts have also criticised the plan as ineffective. Outspoken child protection campaigner Hetty Johnston from the organisation Bravehearts blasted the proposal from Home Affairs Minister Peter Dutton as “a political stunt” and said it would do little to keep children safer.

But Senator Derryn Hinch, a long-time campaigner for tougher laws on child sex offenders including a public register, said he could “now … die happy”.

Mr Dutton announced on Wednesday he had written to the states - who have responsibility for laws on sex offenders registers - just before Christmas proposing the national scheme.

“We're saying that if you live in your postcode, you should know who in your postcode has a history of committing sexual offences against a child … It'll be a name, a photograph, it'll be the history, the charge that the person's been convicted of,” Mr Dutton said.