He said the lagoons along Likas Bay were for flood mitigation and any reclamation efforts would lead to severe flooding in the city.
He said floods have been increasingly severe in recent years and urged the state government to prevent any reclamation work at the lagoons.
Yong, a nominated assemblyman and former chief minister, said the lagoons have helped capture water runoff from the Likas ridge along Tuaran road and the Likas residential areas.
“The development of the Likas ridge, which was previously strictly restricted and controlled, has already caused a heavier runoff of rainfall,” he said on Wednesday (Dec 29).
“(The area) needs huge drains to channel the water into the lagoons before it enters the open sea.
"During high tide, the floodgate at the Likas lagoons will shut and the pumps will remove the floodwater," he said, adding that these mitigation measures were put in place after the devastating 1988 floods.
He said the Department of Irrigation and Drainage (DID) should study the effects of zoning a tract of land in the area, about the size of 40 football fields, for commercial use.
He said this study was important to DID's plans to improve drainage in Basin 8, which includes the Damai and Dah Yeh Villa areas.
“I am shocked to have found out recently that part of the Likas lagoons have been zoned for commercial development. This should not be allowed,” Yong said.
“A search at the Land Department last week revealed that (this) was approved to a private company in 2000," he added.
According to Yong, some residents at Kg Likas said they were worried that Kg Likas and other areas will be flooded if the reclamation goes ahead.
He pointed out that the recent floods in Taman Sri Muda in Selangor should serve as a stark reminder that there could be dire consequences if land meant for water retention is later reclaimed for development.