From the Disability Strategy
The key principle and outcomes associated with web design/user experience elements are:
Key principles
v. Remove barriers and increase accessibility in all environments.
Outcomes
5. Barrier-free access – Barriers to accessibility are properly identified, addressed, and removed. Adopt Universal Design principles and practice across all environments.
W3C Web Accessibility Initiative provides a list of resources and training material to help with incorporating website accessibility.
The New Zealand Government has some accessibility guidelines. See the following links.