A dispute between Mayor Michael R. Bloomberg and Gov. Andrew M. Cuomo over the $1 billion museum at ground zero has dragged on for so long that the museum will not open in time for the 11th anniversary of the Sept. 11 attacks — or even for the next one.

Aides to Mr. Bloomberg and Mr. Cuomo have so far been unable to resolve their differences over which government agencies will pay the operating costs of the museum, which is intended to document the terrorist attacks of 2001 and honor the nearly 3,000 victims. The two sides also remain at odds over who will have oversight of the museum and the surrounding memorial.

The negotiations are further complicated because Gov. Chris Christie of New Jersey must sign off on any agreement before it can take effect. Mr. Cuomo and Mr. Christie together control the Port Authority of New York and New Jersey, which owns the World Trade Center site. Mr. Bloomberg is chairman of the Sept. 11 foundation, which controls the National September 11 Memorial and Museum, and oversees commemorative events at the site.

With work on the museum at a standstill for nearly a year, fund-raising and donations have fallen, and exhibits are gathering dust in fabrication shops in Buffalo and Santa Fe, N.M., according to museum executives.