The flatwater venue, part of a plan to include regional Queensland in Australia's third Summer Olympics, initially attracted attention because of the presence of some 500 saltwater crocodiles in the river.
Concerns later focused on the river's current but the report has cleared it to "provide a safe, fair and consistent field of play", organisers said in a statement.
"The assessment included extensive on-water investigations and modelling to understand how the course would perform under a range of conditions, weather patterns, water levels and flood risk at both Games time and throughout the period leading into the Games," the statement said.
Queensland Premier David Crisafulli told the state parliament on Thursday that the waterway, which is some 600 km (370 miles) north of Brisbane, had been cleared "with flying colours".
"Many have said it can't be done," he said. "We back in regional Queensland - no ifs, no buts. Our commitment has been steadfast, and our message is clear: regional Queensland can and will host events on the world stage."
World Rowing President Jean-Christophe Rolland said he had demanded a robust assessment of the proposed course to ensure fair and equal conditions for the competitors.
"We now know that the Fitzroy River is capable of providing fair competition conditions during the period of the Games, consistent with the requirements of Olympic and Paralympic Rowing," he said in the statement.
Paddle Worldwide, which will organise the canoe sprint event, also endorsed the findings of the report.
"The quality and depth of the technical work undertaken has significantly improved our understanding of the field of play and provides confidence to us and our athletes that the course can deliver fair competition," President Thomas Konietzko said.
"We look forward to maintaining our strong partnership and continuing to work together to deliver an outstanding Olympic and Paralympic competition venue in Rockhampton for 2032."
Brisbane's bid for the 2032 Games was processed through the International Olympic Committee (IOC)'s "New Norms" policy, where existing facilities would be upgraded where possible.
Organisers have nevertheless elected to build a new 63,000-seat Olympic stadium and an aquatics centre in a Brisbane city centre park.