National Grid on Tuesday submitted an application to the state Public Service Commission to raise natural gas delivery rates by almost 7%.

The increase would cost the average Long Island homeowner roughly an extra $6.50 a month.

National Grid says it needs the rate hike to help repair old gas pipes, safety and technology improvements.

"We maintain our focus on customer affordability and are interested in exploring a multiyear rate plan settlement that would allow us to maximize efficiencies over a three- to four-year period," President John Bruckner said in a statement.

Critics of National Grid's rate hike plan predict the latest increase will hit seniors and low- to moderate-income customers the hardest.

Richard Berkley, of the Public Utility Law Project, says his watchdog group will be fighting against the delivery rate hike.

If approved by the Public Service Commission, the rate hike could go into effect in April 2020.