NEW YORK — The World Trade Center disaster will cost New York's economy as much as $105 billion over the next two years, city officials said Thursday as they warned of budget woes even with a big federal bailout.

While the city may limp through this year without major problems, Comptroller Alan Hevesi said billions of dollars in lost revenue will begin causing financial headaches as early as July.

``And that assumes the federal government picks up the major expenses here,'' Hevesi spokesman David Neustadt said. ``If not, then all bets are off.''

After the Sept. 11 attack, Congress appropriated $20 billion to help New York with its recovery. Some of an additional $20 billion authorized for anti-terrorist measures will also end up in New York.

Mayor Rudolph Giuliani and Gov. George Pataki say President Bush regards the aid committed so far as only a start. On Wednesday — as Bush visited New York for a second time — the mayor said the president understands it will be ``very, very expensive'' to rebuild New York.

Just how expensive it may be is daunting.

According to Hevesi, the trade center's destruction cost $6.7 billion; $12 billion was lost in computers and other office equipment; rebuilding the complex will cost $5.3 billion; and the city's economy will lose $11 billion in spending by the thousands of trade center victims.

Hevesi also said 115,300 jobs would be lost this year alone, though that number could be offset by gains in construction and other fields involved in cleanup and rebuilding.

The city's overall economy is estimated at about $380 billion a year.

An early, preliminary estimate of the cleanup and rebuilding by congressional aides placed the cost of the attack at $39 billion — a figure that did not include lost economic activity. Hevesi's analysis says the attack may cost New York up to $105 billion by June 2003 because of lost revenue, damage and rebuilding.

``What this study makes clear is that what the president and Congress have committed so far is just a down payment,'' he said.

The economic costs of the attack have slowly emerged as the search goes on for the victims. As of Thursday, the number of missing remained at 4,986, with the number of confirmed dead rose by 11 to 380.

Longer-term costs are still unfolding, including the damage to tourism.

Flights at the three major airports serving New York — Kennedy, LaGuardia and Newark, N.J. — are down substantially. Delta said its flights from Kennedy and LaGuardia are off by more than 50 percent from pre-attack levels compared with a 32 percent decline nationwide.

The president of the U.S. Chamber of Commerce, Thomas Donohue, visited New York on Thursday along with other business association leaders to boost tourism and urge changes to federal tax laws and policies to aid the economy.

He said there are signs the city is coming back.

``I was in town early last week and the energy level is up,'' Donohue said. ``There is great sorrow. But the economy is starting to bubble a little. People are starting to get back in sync. Bankers are lending money. People are walking faster. There are more people in hotels.''

The chairwoman of the state Democratic Party, Judith Hope, said she would push for the National Democratic Convention to be held in New York in 2004.

Thursday evening, a memorial service was held at the Theater at Madison Square Garden for the 74 Port Authority employees who died during the attack.