Government agencies use public money to create web content and then prevent people from using it. Wouldn’t it make sense to put content created by public dollars in the public domain?
I find this on Local and Central government websites. Here’s an example from Tenancy Services:
Except where stated otherwise, this website and the information on it is protected by Crown copyright.
You may reproduce information on this site for personal or non-commercial use without formal permission or charge as long as you clearly indicate that the website of Tenancy Services is the source of the information, any disclaimers applying to the information are reproduced, and that the material is not sold or used in an inappropriate or misleading context having regard to the nature of the material.
Tenancy Services holds copyright or licence rights to all images and trademarks on this website, including the Tenancy Services logo. Images and trademarks on this site must not be used or reproduced for any purpose, including personal or educational use, unless the written permission of Tenancy Services has been obtained.
The OP posted usage terms that included trademarks hence why I mentioned it.
In terms of special rules for government, I don’t think it’s necessary. Current rules for trademarks, copyright, and patents should cover IP. But what the government maybe should do it write a specific licence governing the use of government work.
NZ already has official information laws that require most government information to be provided on request, but the government still holds the copyright as like others have said you don’t want people copying your government sites looking official.