All the passengers on the flight, from Newark Liberty International Airport to Warsaw, are safe and uninjured, she told CNN. Newark Liberty serves the greater New York area.
The LOT Polish Airlines flight, which had been due to land at 1:35 p.m. local time, circled above the airport for an hour before coming down in a belly landing at 2:40, she said.
"After noticing a central hydraulic system failure the standard procedure for emergency landings at Warsaw airport were implemented," LOT said in a statement, saying emergency crews were in place on the ground to assist.
There were 231 people aboard the flight, 220 of them passengers and 11 crew, the airline said.
The passengers "stayed calm" during the emergency landing and after reaching the terminal were cared for by support staff and psychologists, the airline added.
Video footage from the scene shows the plane coming in to land without its wheels down. Emergency vehicles can be seen racing towards the aircraft moments after it lands and appearing to hose it down as passengers disembark.
The airport is Poland's busiest, handling almost half its air passenger traffic with about 100 scheduled flights a day, the airport's website says.
LOT, the Polish flag carrier and one of the world's oldest airlines, is currently offering special deals on flights from the New York area to Warsaw.
In 2010, it carried more than 4.5 million passengers, nearly three-quarters of whom were on international flights, its website says. The airline said it aims to offer quality of service and value for money.