Signs warning the public to stay out of Nuuanu Stream below Beretania Street are to be posted Monday morning after a 2,250-gallon wastewater spill.

The city Department of Environmental Services responded to the spill at about 6 p.m. yesterday on the Beretania Street side of Aala Park.

The spill was caused by grease clogging a 10-inch terra cotta pipe, the city said. A city crew diverted about 1,250 gallons into a nearby manhole and cleaned, disinfected and deodorized the area.

The wastewater discharge happened on the Beretania Street side of Aala Park. About 850 gallons entered a storm drain that empties into the stream and Honolulu Harbor, the state said.