National Grid’s proposed 24 percent delivery rate hike received sharply critical reviews from a handful of opponents at a hearing Tuesday night, all denouncing the increase as unaffordable.

The public hearings Tuesday and Wednesday come as National Grid and the state are already engaged in a settlement process in the case, in which National Grid seeks $146 million in delivery rate increases atop $33 million in new annual toxic-site remediation surcharges. Evidentiary hearings in the case are set for September.

The few ratepayers who spoke about the hike said Long Islanders can’t afford the roughly $16 average monthly increase.

Rachel Burd, a coordinator for the Public Utility Law Project, a low-income utility watchdog group, said existing and proposed rates place an “extraordinary burden” on National Grid customers, almost half of whom already can’t afford their utility bills.

She noted National Grid’s “particularly egregious” practice of seizing electric meters to shut off service when customers fall behind on their bills, and she said the company has failed to help eligible low-income customers access available discounts.

Last year, she said, 13,524 customers had their service shut off by National Grid on Long Island and in the Rockaways, a jump from the 9,852 in 2014.

Thomas Gallagher, a ratepayer from East Meadow, predicted a rippling effect of the increase, which he said would impact everyone from homeowners to pizza shops.

“Many people cannot afford to live here on Long Island,” Gallagher said. “We’re going to have to put a stop to this raising of rates.”

Two National Grid employees at the hearing did not publicly explain the rate case.

One who declined to give his name said the hearing was intended for public comment, not company information, and pointed to voluminous documents on a state Department of Public Service website.

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Officials at the local DPS office also didn’t speak, and one said the acting director of the Long Island office, Guy Mazza, “couldn’t make it.”

Chris Widelo, associate state director for AARP, said he spoke for 500,000 members in calling the increase “too high” and asked the state to reject it.

“We believe this rate increase will threaten the affordability of essential natural-gas service for vulnerable customers,” he said. More than 22,000 Long Island seniors were below the federal poverty level in 2013, up from 6 percent in 2009.

Between 43 percent and 84 percent of senior households have received public assistance in that same time, he said, and nearly half of them in a survey expressed concerns about being able to afford utility costs.