A United Airlines flight from Newark International Airport in New Jersey, US has been grounded after a passenger spotted a huge fuel leak as the plane sat on the tarmac waiting to take off.

The passenger said she and her husband were on their way to Venice, Italy for their honeymoon when she looked out the window and saw the fuel pouring out from the edge of the left wing.

She said no-one was reacting, so her husband ran to the back to inform flight attendants of the problem.

TWITTER/RACHELEPAS VIA STORYFUL The United Airlines flight was scheduled to go from Newark, US to Venice, Italy when the leak was spotted.

The flight attendants, though, yelled to him to sit back down.

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Once he had, she said, the flight attendant ran to the cockpit before the engines turned off.

On Twitter the passenger, known as RachelEPas, said: "How not one crew member saw this is beyond me. Thank god we were lookin (sic) out the window at take off."

Clearer video of the #united #gasleak. How not one crew member saw this is beyond me. Thank god we were lookin out the window at take off. pic.twitter.com/3BDZJ3S4xd — Rachel (@RachelEPas) June 14, 2017

United representatives told NJ.com the passengers were put in hotels. But RachelEPas said that wasn't true. Some passengers were given hotel vouchers, but many, including her and her husband, were not given anything more than a food voucher.

Many people from the flight were sleeping on the floor in baggage claim, she said.