The self-confessed "tree hugger from way back", who wrote the song for his erstwhile band Men at Work, says in the generation that has passed, the problems have only intensified.
"There's a great unconsciousness about the fact there is a whole continent and 20 odd million people get to run it and to be in it and to look after it, and I don't think we're doing a particularly good job," Hay told AAP.
"Its about being good caretakers of the country, which I don't think we are."
Over four decades, Down Under has become synonymous with true blue culture. As Aussie as Vegemite.
The global number one became an anthem for Australia's 1983 America's Cup win, was used in Crocodile Dundee II and was sung at the Sydney Olympics in 2000 - not to mention arm-in-arm in bars around the world.
Not bad for a song that only took Hay 40 minutes to write.
"Those 40 minutes have looked after me for the last 40 years," Scottish-born Hay laughs.
But while the video and verses are a quirky, satirical take of a larger-than-life Aussie travelling abroad, to Hay the the song was really about his fear of "the man".
"My fear was the corporate world, the conservative world I didn't want to belong to, and I still don't want to belong to," Hay says from his home in the Los Angeles mountains.
If he were writing it now, he would still be issuing the same call-to-action, he says.
"Things are a lot more time sensitive now ... they are getting to a tipping point," he says, adding world leaders are failing on issues like climate change.
"It makes me worry about the future - of not the planet so much but humanity's place in it."
When the global pandemic put the entertainment world on hold, Hay found an opportunity to revisit and reflect on songs from his past that held meaning for him.
What started as a sentimental trip down memory lane resulted in an album of covers that took Hay on a personal journey.
"It was strangely emotional because I got to revisit those songs and what they meant to me - not only now but what they meant to me then," he says.
"You have these emotions stored away inside and you're unaware that they'll be released when you revisit those songs. It's an interesting process."
The album includes Hay's versions of The Kinks' Waterloo Sunset, The Beatles' Norwegian Wood and the title track I Just Don't Know What to Do With Myself, originally sung by Dusty Springfield.
An eclectic mix, not meticulously curated but simply songs that sprang into his head, he says. His emotional connection to them is felt throughout.
No surprise, then, that his connection to Down Under is felt so much deeper.
"It really is like an old pal," he says.
"And 40 is a good number."
AAP with The Project