"Zurich leads the way, followed by Sydney, London, Milan, Stockholm, Copenhagen, NYC, San Francisco, Amsterdam and Madrid," they write.
"Tokyo is among the most expensive cities on most measures but surprisingly cheap hotel rooms (more akin to [emerging market] prices) help push it below many others."
For two nights at a five-star hotel room, two pub meals for two, two restaurant dinners for two, car rentals for two days, two pints of beer, four litres of soft drinks or water, and a bit of shopping (a pair of jeans and a pair of sports shoes), Sydney will set you back US$2320 ($3206.83), compared with US$2475 ($3421.08) in Zurich.
Australian cities rank in the top 20 according to the 'Cheap Date Index' - defined as taxi rides, dinner or lunch for two at a pub or diner, soft drinks, two movie tickets and a couple of beers.
In Melbourne, all of the above will cost you US$112 ($154.81), making it the 18th most expensive city for romance. Sydney came in just behind at US$111.30 ($153.85).
"At the other end of the scale, cities in Malaysia, India and South Africa are the cheapest for a weekend away and around a third of the cost of the most expensive places," the report says.
"For those wanting a real cheap 'cheap date', India, Indonesia, the Philippines and South Africa are the places to go. Indeed in all of these places you can have at least four dates for the price of one in Zurich, but please don't tell the other three people!"
If you're heading to Rio for the Olympics, don't drop your iPhone. Brazil is the most expensive place in the world to buy an iPhone 6 at US$931. That's 156 per cent more expensive than the US.
Australia ranks 13th in the iPhone rankings, with an iPhone 6 costing US$707 ($977.25), or 118 per cent more expensive than the US.
Other measures in which Australia ranks among the most expensive in the world include five-star hotel rooms, movie tickets, two litres of Coca-Cola, and public transport and taxi costs.