A 22-year-old man died at the festival near Lexton in central Victoria, which this year ran for five days in late January. Two sexual assaults, six drug trafficking charges and four road crashes were reported in relation to the event. Police said one in eight drivers tested for drugs returned a positive result.

Ballarat's Superintendent Andrew Allen said the festival posed "extreme risks" to other road users. He said he would "categorically be agitating for a reduction in the length of the festival".

"This elevated rate of positive tests from the event is completely unacceptable and something has to change," he said. "More responsibility must come from the festival organisers in relation to the impact this has on the community."

Festival organiser Tim Harvey​ has rejected the police's criticisms, saying the event should be lengthened to allow revellers time to recover from partying before they drive home.

Now in its 20th year, the bush bash attended by nearly 20,000 people annually has come under fire for drug-related incidents in recent years including deaths, drug-driving and drug trafficking, as well as sexual assaults.

The family of 22-year-old Jacob Langford, who died at the festival on January 28, has criticised organisers for not providing a safe environment.

Police have neither confirmed nor denied reports Mr Langford's death was caused by consuming amyl nitrate, a liquid substance sold as DVD or leather cleaner. The coroner is investigating the death.

Mr Harvey issued a statement at the time saying the festival "considers the safety of patrons a priority and we will continue to co-operate with authorities to determine exactly what happened in this situation".

At the 2016 festival, police arrested more than 40 festival-goers for driving under the influence of drugs or drug trafficking, and recorded four sexual assaults.

Another reveller died in 2012 from drug-related causes, and in 2013 the festival nearly didn't go ahead due to permit issues around safety concerns.

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Mr Harvey played down the link between the festival and drug driving, saying one in eight drivers testing positive was "a fantastic result when compared to the Victorian community in general", with similar figures reported for driver testing over Easter.

"We know wherever in the world there are more cars, there is more chance of traffic accidents so we don't think that statistic is isolated to the event," he said.

The festival was "always looking for evidence-based approaches to producing a safer event environment" and the issues were not just faced by the Rainbow Serpent Festival but "the Victorian community as a whole", Mr Harvey said.

"We strongly believe it would be counter-productive to put more cars on the road in a shorter time frame with less rested drivers," he said.

"A more realistic option, if safety is the key concern, would be to lengthen the event to include an extra day with no entertainment so our patrons can rest and revive before departing the festival site."

The festival ran for one day longer than usual this year, as it fell on the Australia Day holiday.

Superintendent Allen said festival organisers had already taken on board some suggested changes, but further changes would be pursued.

Rainbow Serpent's organisers did not respond to specific questions from The Age about which changes they had implemented or would consider implementing.

This year, however, they introduced an inclusive "safe space" initiative called The Nest, with sexual assault counsellors and psychologists on the ground to respond to alleged assaults.

with Olivia Shying and Brendan Wrigley, Ballarat Courier

What do you think? Would shortening the Rainbow Serpent Festival make it safer? Let us know in the comments below.