Honolulu police are looking into allegations that a private manager of the city's Waimanalo Gulch landfill received payoffs from companies that dump debris there.

Waste Management, the company that operates the site, said it had placed the manager on paid administrative leave and launched its own probe.

"The company is investigating the matter and is fully cooperating with local authorities, including the Honolulu Police Department," Waste Management said in a prepared statement.

A city employee informed police of the allegations, according to city officials. Police have contacted people about the claims but stopped short of calling the inquiry a formal investigation.

The manager in question did not return a call to his home yesterday.

Though no wrongdoing has been proven, the scrutiny comes at a bad time for the controversial landfill, located near Kahe Point on the Leeward Coast.

The city and Waste Management plan to seek state permission to expand the landfill and continue operating it for 15 years after its current permit expires next year.

Meanwhile, the company is still disputing a $2.8 million fine the state Health Department issued last year over numerous health and permit violations at the landfill.

State Senate President Colleen Hanabusa, who represents the Leeward Coast and has long opposed the landfill, said the new allegations were disturbing.

"It just seems like one thing after another there," said Hanabusa, who lives in the Ko Olina resort complex across Farrington Highway from the landfill.

Waste Management said it "is committed to the people and businesses of O'ahu and providing safe and environmentally sensitive trash disposal on the island."

City Councilman Todd Apo, who also represents the area, said the landfill's problematic history raises serious questions about whether any expansion should be allowed.

"Apparently, there are still some significant problems there," he said. "We need to let the investigation happen, and once we get the results, act accordingly."

City and private trash haulers dump about 800 tons of trash in Waimanalo Gulch per day, plus an additional 600 tons of ash from garbage incinerated at the H-Power electricity generation plant.

Reach Johnny Brannon at jbrannon@honoluluadvertiser.com.