If this city is in dire straits, don't tell it to the hotel industry, which in recent years has been big-bucking a trend towards spiffier and more modern lodgings for visitors to the world's top tourist destination.

The clatter of jackhammers and other machinery that has been rocking the Big Apple to its core is now beginning to fade as the hoteliers make plans to unveil the fruits of their labors over the next few months. By December, almost 4,000 rooms will be welcoming visitors in four new hotels and in two others that have been totally renovated.

In addition, about a dozen other hostelries will have completed extensive renovations to their guest rooms as well as their lobbies and other public meeting places. The total cost of the new hotels and renovations runs into the hundreds of millions of dollars.

Here's a rundown on some of the deluxe digs that are, or soon will be, welcoming guests:

Palace Hotel (Madison Avenue at 50th St.): Expected to be fully open by October, the more than $100-million, 51-story hotel will be the tallest and according to builder Harry B. Hemsley, the most luxurious hotel in New York City. The 1,050-room hotel includes 775 double rooms and 103 suites ranging from one-bedroom to four-bedroom duplex and triplex accommodations. The hotel is behind and part of the historic Villard Houses, 100-year-old Italian Neo-Renaissance landmark buildings, and incorporates many of the historic interiors as public rooms. It is the first time a landmark building has been adapted for use in new hotel construction.

Grand Hyatt (Park Avenue and Grand Central): Opening the first week in September, the 1,400-room Grand Hyatt is a reconstruction and remodeling of the former Commodore Hotel, at 42nd Street and Lexington Avenue. The project cost more than $100 million. Features of the 30-story hotel are a four-story, plant-filled atrium lobby with a cascading waterfall, and a glass-enclosed cocktail lounge, cantilevered over 42nd Street.

Vista Internationa (3 World Trade Center): The 825-room hotel, due to open in mid-November, is Hilton International's first hotel in the continental United States. Located betweem the towers of the World Trade Center, it is the first major hotel to be built in the city's financial district since 1836. Costing more than $56 million, the 22-story hotel will have a fitness center with supervised programs, racquetball courts, jogging track, swimming pool, turkish and sauna baths and gymnasium.

Harley (214 East 42nd St.): The $42-million, 38-story hotel, opening in November, has 793 rooms. Built on the site where the former Central Commercial High School once stood, the hotel is the flagship of the new Harley Hotel group, a division of Hemsley Hotels, which includes 23 hotels and motels around the country. Hemsley is also the builder of the Palace Hotel. Two of the features of the hotel will be a lobby-level restaurant with a 12-panel mural depicting historic scenes in the city's history, and a landscaped open-air plaza on 41st Street.

Parker Meridien (118 West 57th St.): A joint venture of Meridien Hotels, a wholly-owned subsidiary of Air France, and the Jack Parker Corp., a diversified developer and operator of luxury buildings in New York, New Jersey and Florida, the Parker Meridien has set Nov. 24 as its opening date. The hotel rises 40 stories, plus one penthouse level, and has 600 rooms and 100 hotel apartments.

Features of the $40-million hotel include a rooftop swimming pool and bar plus complete health-club facilities, four squash courts and four racquetball/handball courts.

Milford Plaza (270 West 45th St.): Completely renovated at a cost of about $20 million, the Milford Plaza recently opened as New York's newest moderately priced hotel. The 1,300-room, former Royal Manhattan Hotel features a brasserie-style restaurant, two lounges and a three-story-high white-marble atrium lobby with a bar.

While other top New York hotels may not have changed outwardly, inside there have been some extraordinary modeling. Some of the hotels that are spending a million dollars and more for renovation and redecoration include:

Sheraton Centre (Seventh Avenue and 53rd St.): The Sheraton people are spending $42 million to upgrade and remodel their Manhattan properties. About half of it went to the Sheraton Centre, the former Americana Hotel, where the top five floors, 46 through 50, have been turned into the Towers.

Tower guests get more deluxe accommodations and other special amenities. The hotel lobby also has been converted into an atrium complex, with a new 24-hour restaurant, the Cafe Fontana, being its highlight.

The St. Regis-Sheraton is also undergoing a $16 million renovation, including an exterior facelift for the first time in 75 years, and a refurbishing of its rooms and suites.

Loews Drake (Park Avenue and 56th St.): All 640 rooms and suites, as well as the public rooms and lobby, have been completely done over at a cost of $15 million. Changes can be immediately seen in the lobby, which now has a concierge, hand-woven rugs, an elevated cocktail lounge and a new restaurant, the Wellington Grill.

Other major changes at Loews holdings in the city include a $1.5-million project at the Regency (Park Avenue and 61st St.) where all 22 of its Tower Suites have been completely refurbished, and the creation of a special ESP (Extra Special Patron) floor at the Summit Hotel. The $1-million undertaking at the 800-room Summit (Lexington Avenue and 51st St.) covers the 17th floor and includes more deluxe accommodations and many special amenities.

Berkshire Place (21 East 52nd St.): The original Berkshire Hotel, built in 1926, has gone through a $9.5-million restoration project. New featurse to the 425-room hostelry, which is now part of the Dunfey Classic Hotel group, include an Atrium Lounge and a new restaurant, the Rendez-vous, with an adjacent sidewalk cafe.

Marriott's Essex House (160 Central Park South): Celebrating its 50th anniversary next year, the 860-room Essex House has completed the last phase of a $5.2 million room renovation program.

Rates for a double room at one of the new or renovated hotels run from $150 a day at the Palace down to $49 at the Milford. You can figure on spending about $100 at the other hotels.

The newest "in" things at many of the hotels are open lobby cocktail lounges and special floors. Accommodations on the floors -- which may be called VIP, ESP, Concierge, Executive, Towers -- are better but they also cost more, about $20 a day. Amenities on the more expensive floors range from special check-in and check-out, express elevators, a floor concierge, free continental breakfast and evening liquors in a private lounge, to such gratis goodies as toiletries, fruit, garment bags, shoe horns and the use of heavy terry cloth robes.

You can get an updated folder, "Hotels in New York City," which includes rates for all the new hotels as well as other information on the city, by writing to the New York Convention & Visitors Bureau, 2 Columbus Circle, New York, N.Y. 10019.