The identities and nationalities of the dead were not immediately known.
Officials declined to respond to reports that the fire, which burned for several hours, might have been set by one of the prisoners and that the cells were unsafe.
"They were illegal aliens waiting to be extradited to their countries of origin," said Immigration Service spokesman Martin Bruinsma.
"We are still busy trying to confirm their identities."
An unknown number of detainees escaped during the fire that broke out on Wednesday shortly after midnight and raged until 0300 (0100GMT).
Firefighters and airport police were among the injured, according to the news reports. Four people were hospitalised for treatment.
"We are still busy trying to confirm their identities"
Immigration Service spokesman
A prisoner told the Dutch television station NOS that guards initially did not take prisoners' warnings of a fire seriously and told them nothing was wrong.
"They didn't open the door. They kept us locked up. Our throats started hurting. We were kicking and screaming," said the detainee, who was not identified.
The detention block is located on the east side of Schiphol airport and is surrounded by a three-metre fence and barbed wire.
The sprawling prefabricated buildings were set up in 2002 and are used to detain people who arrive by plane and have been refused entry to the Netherlands - among them drug smugglers and failed asylum seekers.
Immigration policy flayed
About 350 prisoners were being held in the complex when the fire broke out. Uninjured prisoners were taken to other facilities in nearby cities or moved elsewhere within the complex, Dutch media reported.
Helicopters were called in during the fire to track down possible escaped detainees.
Prisoners were taken to other
facilities after the fire broke out
The Netherlands, which has adopted one of the toughest immigration policies in Europe, is in the process of deporting some 26,000 asylum seekers who have been refused Dutch residency.
Rights groups have criticised the policy, saying people have been deported to countries where they could face persecution or abuse.
Hundreds of cocaine smugglers, mostly from the Caribbean and Curacao, are detained at the airport every year, as are immigrants caught trying to enter the country illegally.