New York City's subway system will resume limited operations on Thursday, four days after it was shut down ahead of the arrival of Sandy, the massive storm that brought unprecedented flooding to the world's financial capital, New York Governor Andrew Cuomo said.

Limited service on suburban commuter rail lines serving Long Island to the east and Westchester County and Connecticut to the north was to resume on Wednesday afternoon, Cuomo said at a press conference. Trains were to begin operating on the Long Island Railroad and Metro North Railroad systems at 2 p.m. (1800 GMT) on Wednesday.

Cuomo said the restored subway service would be supplemented by a "bus bridge" between Manhattan and Brooklyn given that four of the seven tunnels connecting the two boroughs under the East River remain flooded. Three of the seven tunnels were now clear of water, he said.

In Manhattan, there would be no subway service south of 34th Street, Cuomo said.

New York City was brought to a near standstill by flooding, power outages and transportation closures after the storm hit Monday night.

The city counts an average of 5.3 million riders each weekday. The system, which runs around the clock, comprises 21 subway routes linked by 468 stations, and stretches across 660 miles (1,062 km) of track.

Cuomo said officials faced huge task to restore not only transportation services but other key portions of the city's infrastructure damaged when Sandy swept a record storm surge of nearly 14 feet (4.3 metres) over southern Manhattan and other low-lying waterfront neighborhoods.

"It was frightening. It was frightening. It looked apocalyptic," Cuomo said of the flooding he witnessed on Monday night at the height of the storm.