With music, food, drinks, merchandise and raffle tickets for sale, spectators will be well catered for and can join the teams at the official after party at Our Backyard Pub from 9pm.
Slam Rock is run by about 30 volunteers and 21 game officials, some of whom are coming as far as Wellington to be involved.
The event is made possible by the Steam Rollers fundraising efforts which include marshalling at other sporting events and securing grants through organisations such as the Rotorua Energy Charitable Trust.
Steam Rollers chairwoman Layla Robinson said the trust had supported Slam Rock financially since 2014.
"Without their charitable contribution, this event wouldn't be nearly as successful as it has become.
"Having the support of RECT and a number of other organisations who have helped us over the years has enabled us to showcase this unique, exhilarating sport and the health and wellbeing benefits it brings to members of our community."
This year, Rotorua team Motley Crew will take on the Salty Rollers from Moana Roller Derby in Tauranga.
The teams are closely matched; Moana is just slightly above the Steam Rollers on the national ranking table.
Roller derby is a full-contact game likened to "rugby on skates". Players skate around an oval track in a pack made up of eight skaters, four from each team, who hold the position of blockers.
Blockers must remain within a certain distance from each other at all times. Also on the track are jammers, one from each team who are the point scorers. It is the jammers' role to attempt to "break" through the pack and score points for each opposition player they pass.
• Slam Rock is on June 30 at the Sportsdrome. Doors open at 6pm, game formalities start at 6.45pm. Food, non-alcoholic and alcoholic beverages will be available for purchase. Tickets on sale now from Ticketmaster.