Alcohol causes more than twice as many festivalgoers to seek medical attention as other drugs, St John says.
St John event risk manager Glen Hoult revealed the data in a submission before the Parliamentary Health Committee in support of the Drug and Substance Checking Legislation Bill, which recently passed its first reading in the house.
It replaces the temporary Drug and Substance Checking Legislation Act 2020 passed in December under urgency, allowing drug testing organisations to operate at festivals.
The bill was temporary, rushed through ahead of the busy summer period, and expires this December.
Hoult said their organisation "wholly supports" the legislation, and itself was seeking to become a qualified drug-checking outfit.
"It is a fantastic move. Another provider in the market prior to now has had to operate in a shady part of the law, and St John has always wanted to be involved in drug harm reduction including drug checking but until now was not able to."
Hoult said about 70 per cent of patrons who present themselves to St John's medical tents at concerts and festivals are in some way intoxicated due to alcohol or drugs.
About 50 per cent of those were due to alcohol intoxication, about 20 per cent due to drug intoxication and the other 30 per cent a result of typical medical and trauma-related injuries.
The main suggestion St John had for the legislation was to allow for "high-level" data collection, such as age, ethnicity and gender, while protecting privacy.
Currently this was not allowed in the bill, but Hoult said this data would be useful for drug prevention research.
The Drug Foundation also submitted in support of the "world-first legislation", and proposed a "public interest" exemption be added to the country's drug laws to enable quicker and easier establishment of future harm reduction initiatives that could save lives.
Executive director Sarah Helm said such a clause would ensure "future harm reduction and potentially life-saving initiatives are able to be rolled out quickly and easily".
The National Party has opposed the bill, National MP Simon Bridges saying in May his views hadn't changed much since the first temporary bill was passed last year.
Meanwhile the youth wing, the Young Nats, supports the bill.
President Steph Ross told the select committee the evidence to support the bill was "overwhelming".
"The reason we are making this submission today is because drug and substance checking reduces harm - if a young person makes the decision to take an illicit drug, it should not be a death sentence."
Know Your Stuff Managing Director Wendy Allison told the committee they supported the bill, which would legalise the work her organisation has been doing for free for the past seven years.
Allison said the legislation should make clear service providers should focus on harm reduction principles, and provide more clarity around training procedures and timeframes around possessing drugs allowing for testing purposes.
They also supported some information being recorded to help with health research.
Note: An earlier version of this story included incorrect figures provided by St John. They have since been amended.