New York City Mayor Michael Bloomberg said he is "extremely dissatisfied" with the performance of the city's emergency response system in the wake of a Boxing Day blizzard that blanketed the region in a deep layer of snow, and pledged to hold an inquiry into the matter.

During a news conference on Wednesday, he said the city's plan for dealing with intense storms had failed in this case. But he commended the ongoing battle to dig the city out after heavy snowfall.

"Our city is using every single resource at our disposal and many more that we've borrowed and hired to get the five boroughs back up and running," he told reporters. "But obviously we still have a lot more work ahead of us."

Yesterday the city hired 700 private labourers to help clear bus stops and crosswalks, he said. Another 1,200 joined them today, and will continue shoveling on Thursday.

Bloomberg's comments come amid growing signs of frustration among residents and travellers in the area who have been affected by the severe weather.

One video posted online showed city residents shouting at workers who had collided with a parked car while trying to extricate a trapped construction vehicle. The video promptly went viral.

The blizzard also crippled New York's three main airports, forcing the cancellation of more than 5,000 flights.

New York's John F. Kennedy airport was reporting minimal flight delays Wednesday, but the situation there remained far from normal. Thousands of stranded passengers have camped out in airport terminals and fought over taxis, rental cars, food and hotel rooms while waiting for their flights to depart.

Tommy Mokhtari, of Dubai, was trying to leave the United States days before his three-month tourist visa expires.

"I waited four hours in the queue just to speak to someone, just to get the news that I have to wait a few more days," he told The Associated Press. "They really need to have a backup plan. I will never ever travel again in December, never on American Airlines, and never through New York."

JFK, Newark Liberty International Airport and LaGuardia Airport were all struggling Wednesday to clear the massive backlog of flights.

By Wednesday morning, all three airports were reporting that most scheduled departures were on time, but that it would take some time to catch up, said CNN's Susan Candiotti, reporting from JFK airport.

"Those problems that have been going on for the past 48 hours are still going on today -- evidently a number of international flights coming into JFK from overseas were sitting on the tarmac last night after landing and sat on the tarmac for a good six, seven, eight and even nine hours before space became available for them to pull up to the gate," she told CTV News Channel.

Airlines had been told not to depart for JFK unless they were told gate space was available, Candiotti said.

"A spokesperson here at the airport today told me 'we told them they had to do that,' but apparently in his words 'it didn't help.'"

In one case an Air China plane landed at JFK and waited for five or six hours, Candiotti said. When a gate finally opened up, the plane had to be towed in because the crew had reached the end of their flight time limit, and could no longer legally operate the plane.

On Tuesday, a British Airways jet and two Cathay Pacific planes were stranded on the tarmac at JFK for more than seven hours while waiting for an open gate.

There were reports that others were stranded on runways for up to 11 hours.

Tuesday night and into Wednesday, the New York airports were still crammed with stranded passengers trying to make alternative plans or find places to stay while they waited for their flights to be rescheduled.

Steve Coleman, a spokesperson for the Port Authority of New York and New Jersey, which operates the NYC and New Jersey airports, said airlines were dispatching planes to JFK without lining up gate space first, adding to the backups.

While the airports were digging out and trying to get flight schedules back on track, other services across New York also struggled to recover in the wake of the storm.

Snow-clearing crews were woefully behind and many streets remained snow-filled, with hundreds of buses and ambulances stuck in snowdrifts.

Tow trucks worked to clear dozens of vehicles left abandoned on major highways in the New Jersey area.

Subways and commuter trains were for the most part, working, but were behind schedule and some lines were shut down.

In a video posted to YouTube that quickly went viral, a New York City resident shouted expletives at a tow-truck driver attempting to free a stuck plow. In the process, the plow repeatedly slams into a parked SUV, damaging at least one other vehicle.

Some 1,000 vehicles had been removed from three major New York expressways. Officials said they hoped to have streets cleared by Wednesday, but there were no guarantees.

With files from The Associated Press