I live in Australia and having worked in retail for five years I heard people using Sir and Ma'am a lot. It always felt a little weird calling someone ma'am though... Another common one here for women is actually the un-abbreviated form 'Madam'.

One of the guys I worked with used to call the women 'Madam' all the time though and I remember this one lady got really angry at him because she said she didn't run a brothel. o_o No idea where she got THAT idea from!