Weeks after massive floods swept through the Kimberley region untreated waste from Fitzroy Crossing is flowing into Martuwarra Fitzroy River from a pipe broken during the disaster.

National Indigenous Times was provided video of wastewater streaming into the river by concerned locals.

Water Corporation North West Manager Sharon Broad said the flooding has caused widespread damage to critical infrastructure, including to a traffic bridge spanning the Martuwarra (Fitzroy) River.

"Running along this bridge is a pipeline that conveys wastewater from Fitzroy Crossing townsite to a nearby treatment plant. Despite significant transport and logistical challenges, crews and materials arrived in Fitzroy Crossing last weekend to begin repairing the damaged pipeline," she said on Friday.

"About 80 metres was replaced on the eastern side of the river. However, heavy rainfall has since caused the river to rise, reflooding the worksite. Crews from Water Corporation and Main Roads are working to reinstate safe access to the site so that repairs can recommence as quickly and safely as possible.

"Advice remains to avoid swimming or fishing in the river given contaminants from several different sources may be present. Further information is available on the WA Department of Health website."

Ms Broad said every effort is being made to complete repairs as quickly and safely as possible.

"Water Corporation thanks the local community and emergency response agencies for their support to our crews during this challenging time. Residents impacted by floods in the Kimberley can access financial support for their water and power bills by visiting Water Corporation and Horizon Power's websites," she said.