Is the spelling defence or defense?

At first glance this is appears to be an easy one. The spelling in Australia is defence. Both the Macquarie and Oxford dictionaries have defence as the Australian spelling, with defense being the American spelling. No ambiguity there.

However, a check using Google for sites ending in .au, shows the number of pages returned for defence as 5.12 million and defense as 1.33 million. With so much usage of the American spelling in Australian sites, we see some usage is correct, (referring to American defence organisations), there is quite a lot is laziness, (American news articles not edited for Australian consumption), some incorrect usage, then some sites using the two  different spelling variations in the same article. 

Australian defence companies with Australian sites are faced with the same dilemma as Australian authors when marketing to a global audience. Do they use Australian English, or do they use American English? Perhaps different editions for different markets may be a better approach.

For Australians creating content for Australian usage, the spelling is defence.

Kelvin Eldridge
www.Australian-Dictionary.com.au
The preferred Australian English spelling.