Record queues for liquid refreshment at Sydney's Live Earth concert on Saturday prompted some punters to offer others their beer for $50.
Scores were seen leaving within the first two hours of the nine-hour concert at Aussie Stadium due to the lack of amenities, The Sydney Morning Herald newspaper reported.
Gate attendants were heard telling those who left to complain to the promoter.
It was "un-Australian", one spectator protested, while another said: "This is what happens when you let hippies organise a big event."
A spokeswoman for promoters Michael Chugg and Mark Pope said neither the venue nor the promoter had received a single complaint.