I’ve noticed for a while that people have been saying “no worries” for what I used to say “don’t worry about it,” or less formally, “no problem.” (There was a short time when “no prob” was floating around, but I havent noticed it in a while.)
Any ideas?
I didn’t really notice it as being popular until Crocodile Dundee came out in the 80’s. Some of our Aussie Dopers will probably come in here and say they’ve been hearing it forever.
It’s an Australian expression that has, indeed, been used here forever.
And by “forever” I mean that it dates back at least to the 60s, and possibly much earlier.
It was such a common part of Australian idiom by the 1950s that it was one of the examples of odd Strine in “They’re a Weird Mob”. Since it was clearly generationally accepted by then, I’m guessing it’s been common in Australia since the 1920s at least.
As for its current US popularity, I suspect that its inclusion in the chorus of one of the songs in “The Lion King” helped to popularise it for the younger generations.
As a possibly relevant datapoint, Scots have used “nae bother” for a long time. I was collecting for charity on the street in Scotland 20-something years ago, and several people I shook the tin at indicated their unwillingness to donate by using that phrase. But it also indicated willingness to help when one was being apologetic about inconveniencing someone.
I seem to recall noticing it being used in British Columbia, as well. Perhaps a case of convergent linguistic evolution? 
Another American who first recalls hearing it in Crocodile Dundee (1986). Really didn’t seem to take off in the US until the mid-90s to the best of my recollection.
I’m a huge fan of the Australian soap opera Prisoner (Prisoner: Cell Block H),which ran from 1979 -1986 and it was a very common expression on that show.
Now if we could get such gems as
“Ah fair go…”
“It’s your shout”
“Would you like a cuppa?”
“fair dinkum”
“Oh wake up Australia”
and the ever popular
“I’m so hungry I could bit the leg off a low flying duck”
To take off I’d be happy
How about “no wuckers”
Well in stages…
“No worries” as a generic Australian thing
then “No worries” as a Crocodile Dundee specific thing
then “No worries” as part of the “Hakuna matata” Lion King song/mantra
In Australia, it’s actually more common to hear “I could eat the crutch [crotch] out of a low-flying duck.”
As for “no worries,” it’s something i’ve said my whole life, and my American wife now uses it regularly.
What about: “She’ll be right!” (used of an inanimate object).
The second and third ones on your list there aren’t specifically Australianisms or Prisonerisms, though; they’re also used in the UK. (Although the third one should probably be “Fancy a cuppa?”)
As for “fair dinkum”… I might be wrong, but in contrast with what the small and big screens would have us believe, in my experience it’s used only occasionally in Oz, and when it is used it’s mostly used adjectivally.
Mid-to-late 20s guy here, and I came in to say this.
Isn’t “good on ya” another Australian import? I heard it during my first visit to Australia in the late 80s, but it’s popped up in the US a lot in the last decade or so.
I actually think of “No worries” more in a Caribbean islander slang context than Australian.
Yes, I think so. The first time I heard it was by Bob Costas during a 2000 Sydney Olympics broadcast.
I guess they had to clean the expression up for TV use. But it was quite common to hear that on Prisoner in it’s “clean” form
I’ve never seen the Lion King but spent about 4 months in Australia/New Zealand in the 1990s and have been using “No Worries” for as long as I can remember.
My impression is that Aussies use it as an idiomatic substitute for “you’re welcome” but that many Americans have repurposed it to mean a more literal, “don’t worry about it” as in,
“I can’t find my pen.”
“No worries, you can borrow mine.”
What is the typical usage in Australia?
It’s both of those things, and more.
If someone says “Thankyou” for doing something, “No worries” is a perfectly good response, and is, as you suggest, the functional equivalent of “You’re welcome.” Not many people in Australia actually say “You’re welcome,” at least compared to the US.
It’s also an appropriate response to an apology. If someone tells you they’re sorry, “No worries” is the equivalent of “It’s not a problem” or “Don’t worry about it.” This can apply to basic public interactions like bumping into someone in the supermarket or a bar, and to more personal things like apologizing for arriving late to a dinner.