Family members of Sept. 11 victims will be able to enter a private room in the World Trade Center memorial and look through a window at a chamber storing more than 9,000 pieces of unidentified human remains, development officials said.

In a "contemplation room" next door, the public will be able to pay respects to an empty, symbolic vessel. Development officials disclosed more information about the design this week as they sought construction bids for the memorial.

The climate-controlled, low-humidity storage chamber for the victims' remains is one of several rooms to be built where the trade center's north tower stood, said Anne Papageorge, who oversees memorial development for the Lower Manhattan Development Corp.

The remains will not be visible from the window, Ellen Borakove, spokeswoman for the city Medical Examiner's office, said Wednesday.

Some family members who follow the trade center rebuilding process said they would have preferred that the victims' remains be entombed in the larger contemplation room.

"Why should the public pay tribute to an empty box?" asked Edie Lutnick, whose brother was killed on Sept. 11, 2001.

Papageorge said that the symbolic vessel isn't large enough to hold the 9,100 unidentified remains and that it wasn't possible to keep it climate-controlled. She said the medical examiner's office also needs easier access to the storage chamber in case it has to retrieve remains.

So far, 1,594 of the 2,749 people who died at the trade center have been identified. The medical examiner's office has said more sophisticated DNA testing may allow additional identifications later. The remains are sealed in refrigerated plastic pouches at the chief medical examiner's office, Borakove said.

The viewing room will be available only to family members, who can access the area by private elevator.

There also are plans within the north tower's footprint for a separate office for the medical examiner, another room where family members can reflect privately and exhibition galleries for the memorial museum.

Some family members said the design cuts up the north tower footprint into too many pieces.

Anthony Gardner, an activist who has sued to completely preserve the twin towers' footprints, said the design destroys the symbolic significance of the land.

"We'll do everything in our power to stop the destruction of the remains of the footprints," said Gardner, whose brother was killed.

Groundbreaking on the memorial is set for March; the memorial is scheduled to open in 2009.