A powerful, powdered form of ecstasy is gaining prominence in Australia as a dramatic rise in police seizures shows the party drug is coming back into fashion.

Experts fear the resurgence of MDMA will mirror a trend in the US towards taking the drug in a powdered version, known as Molly.

The amount of MDMA seized by federal police jumped more than tenfold in the past two years. Some 11.4 kilograms were seized in 2010-11, but this soared to 154.8 kilograms in 2012-13 - with a street value of more than $62 million.

MDMA detections by customs authorities rose from 964 with a total weight of 8.76 kilograms to 4139 detections weighing 149.2 kilograms over the same period.

Pills are still by far the most popular form of MDMA among party-goers, NSW drugs squad commander Nick Bingham said.

However, researchers have been startled by new forms of the drug rapidly entering the market, including capsules, powder or rock crystals - which are seen by users as providing a bigger, better high.

''The quality of ecstasy pills has gone down and people are shifting away from it, so you get this phenomenon of powders being the 'new' drug,'' said Simon Lenton of Curtin University's National Drug Research Institute. ''In the UK, when crystals and powder emerged, researchers found that, whereas young people in the dance scene had been taking pills and wouldn't touch anything else, they were now seeing powder as the 'higher end' form of ecstasy.''

In America, two people fatally overdosed on MDMA at a New York music festival in August.

With New Year's Eve and the festival season in full swing in Australia, Detective Superintendent Bingham warned that party-goers ''should seriously consider'' the possible consequences of experimenting with drugs.

''The majority of drugs are synthetic with no quality control, and what you think you are using is often not the case,'' he said.

Ecstasy use in Australia has been in decline in recent years but, for the first time in a decade, there was an increase in the number of users ranking it as their ''drug of choice'' in the National Drug and Alcohol Research Centre's Ecstasy and Related Drugs Reporting System - from 27 per cent in 2011 to 33 per cent in 2013.

The drug reporting system also found that half of users had noted changes in the drug market in the previous few months, including the emergence of powder, capsules and crystals, a form the researchers had not seen before.

Fairfax Media spoke to half a dozen users about why they had switched from ecstasy pills to powder. Most said they believed it provided a cleaner, stronger high and that more of their friends were trying it.

One user, a 23-year-old nurse from Gladesville on Sydney's north shore, said she and her friends came across a mate selling ''brown sugar'', or MDMA crystals.

''We then did it most weekends for about six months because it was easy to buy,'' she said.

A 26-year-old male user from Carlton North said: ''I'd have caps over pills any day of the week because there's less crap in it.''

The users interviewed said pills, which cost $20-$30, had become unpredictable and could vary from weak products incorporating unknown substances to pills laced with LSD.

The National Drug and Alcohol Research Centre's Dr Lucy Burns said there is a concern that people who would otherwise just have taken pills now see powder as normal drug use. They could potentially go on to dabble in other powders, such as cocaine and methamphetamine.

The use of MDMA in powder form in America has earned it the title of ''the drug of choice for millennials''.

Celebrity musicians Miley Cyrus, Kanye West, Rick Ross, Tyga and Mac Miller have included lyrics about Molly in recent songs.