Travel restrictions and ramped up border security have led to dwindling supplies in Australia and skyrocketing prices.

The US Drug Enforcement Administration estimates a kilo of meth was worth between $US90,000 and $US130,000 ($A128,000 - $A185,000) in Australia before the pandemic, but now sells for around $US200,000.

Cocaine followed a similar price spike, with dealers passing the rise on to the drug users.

"As businesses are having to adjust, every arm of cartels are having to adjust," the DEA's Australia attache Kevin Merkel told the Louisville Courier Journal.

Australia is the cartel's "most sought-after illicit drug market", with Australians more willing to pay a higher price for top-quality Mexican meth than US buyers.

The pandemic has substantially cut air travel to Australia and shut down cruise ship visits, making it difficult to sneak drugs in and take the huge sums of cash they make out.

America's tightened borders have also slowed the flow of drugs and cash over the US-Mexican border.

In Los Angeles, wholesale meth prices have doubled from $US900 per pound at the end of last year to $US1800 to $US2000.

"There's been stockpiling of drugs and money on both sides of the southwest border, and money-laundering activity has decreased," J. Todd Scott, special agent in charge of the DEA's Louisville field division, said.

"People, in general, aren't moving; stuff isn't moving. Cartels function best when they can kind of move undercover, move with the legitimate commerce."

The Courier Journal also found travel restrictions to and from China slowed the importation of precursor chemicals cartels need to make meth and fentanyl.

Australian Associated Press