Spokeswoman Diane Concannon of the American Red Cross of Central New Jersey says additional shelters are opening but supplies and space are limited.
She says those who think they are in danger or their homes might flood should head to a shelter. But she says those whose homes are not threatened by Irene should shelter in place.
The Red Cross says if you do go to a shelter, take these things with you: Medications, spare clothing, copies of important papers, sleeping supplies and snacks. If you have a baby, bring plenty of diapers.
The evacuees from the Atlantic City area were greeted by local police and National Guardsmen but arrived to find few amenities.
"It's a transitional center, not a long-term shelter," said Mary Goepfert of the state's Office of Emergency Management.
She said those evacuees would likely be bused to northern New Jersey later Saturday, possibly to the Izod Center in Newark. She said other shelters were also being considered in central New Jersey.
President Barack Obama declared an emergency in New Jersey on Saturday morning and ordered federal assistance to supplement the state's response to Hurricane Irene.
The action allows federal agencies, such as the Department of Homeland Security and the Federal Emergency Management Agency, to coordinate disaster relief efforts and provide emergency equipment and other resources as needed.
RELATED: Get the latest track of Irene with the 6abc.com Hurricane Tracker.
Mandatory evacuations remain in effect for all of Cape May County, Long Beach Island and coastal communities in Atlantic and Ocean counties. The shore emptied out with relative ease Friday.
Forecasters have said the state will begin to feel the effects of the storm by Saturday afternoon, with the worst due Sunday morning.
The state is busing people in from shore communities to the Sun National Bank Center in Trenton as a staging area and may also make the Izod Center in Newark available if more shelter space is needed.
Yavor Tenev and a group of friends from Bulgaria were working in Ocean City for the summer and had nowhere else to go when the evacuations began.
"There are a lot of people in there," he said, as he and his friends sat outside on a curb enjoying the last of the dry weather to come for a few days.
The group of 20-somethings were moved from a shelter in Woodbine to Trenton and arrived just before 2 a.m., but said there were no cots set up or blankets available so they could sleep. There was also no television, Internet or radios available, so they weren't sure what was going on with the storm.
They were offered food, juice and coffee and no shortage of air conditioning.
"It's freezing in there," said Stahislava Valkova, 21, as she munched on a hot dog for breakfast. "There is nowhere to sleep, only places for the elderly and sick."
Gov. Chris Christie has urged people to use shelters only as a means of last resort.
Public transportation around the state was expected to come to a halt by midday Saturday, as trains stop running and incoming flights are suspended at the New York area airports, including Newark Liberty.
Atlantic City casinos were closed for only the third time since gaming began there in 1978.
While it weakened some late Friday, Hurricane Irene is still supposed to hit New Jersey - or pass very close by - as a Category 1 storm with winds of more than 75 miles per hour and torrential rains.
Six to 10 inches of rain is expected to cause flooding along rivers and streams all over New Jersey, many of them already were swollen after a rainy August.
A storm surge could raise water levels by 3 to 6 feet along the seacoast and the Raritan and Delaware bays. The effect could be even bigger if the storm arrives, as expected, in conjunction with an abnormally high tide around dawn Sunday.
RELATED: How to prepare for Hurricane Irene