Canberra is about 23 times smaller than New Caledonia.

New Caledonia is approximately 18,575 sq km, while Canberra is approximately 814 sq km, making Canberra 4.38% the size of New Caledonia.
Tip: This to-scale comparison of New Caledonia vs. Canberra uses the Mercator projection, which distorts the size of regions near the poles.