David Wallace Newnes is an Australian lawyer and judge who is a member of the Court of Appeal of Western Australia.
In 1978, Newnes graduated from the Law School at the University of Western Australia. That same year, after completing articles of clerkship with the Australian law firm Muir Williams Nicholson, Newnes was admitted to legal practice.
In 1982, Newnes joined Hong Kong law firm Mallesons Stephen Jaques as a soliciter. In 1985, he became a litigation partner with the firm.In 1995, Newness became a litigation partner and head of the litigation unit of the Perth, Australia office of Blake Dawson Waldron, a United Kingdom law firm.
In 2003, Newnes was appointed a Master of the Court to the Supreme Court of Western Australia. In 2007, Newnes became a justice and on 24 February, 2009, was appointed to the Court of Appeal of Western Australia.