WASHINGTON (AP) _ The Navy is defending its new $1.2 billion destroyer in the wake of fresh charges that the ship could be detected by Soviet airborne radar despite Pentagon attempts to make it radar-evading.

''With the Arleigh Burke class, this is the best warship the world has seen,'' Navy spokesman Lt. Bruce Cole said in response to allegations from one lawmaker that the destroyer program is fraught with technical and financial problems.

Rep. John Dingell, D-Mich., who last September called the $33 billion destroyer program a ''procurement nightmare'' of cost overruns and schedule delays, contended Wednesday that the Navy was forced to bail out the destroyer's manufacturer - Bath Iron Works Corp. of Maine.

In a letter to Rep. Charles E. Bennett, D-Fla., Dingell said Bath Iron Works faced serious financial problems and the Navy spent between $75 million to $90 million to save the company. The Michigan Democrat also said the money came from unspecified Pentagon accounts and questioned whether ''slush funds'' were common at the Defense Department.

''Clearly, I think the Navy and the contractors are attempting to hoodwink both of us,'' Dingell said in a three-page letter to Bennett, chairman of the House Armed Services subcommittee on seapower and strategic and critical materials.

The letter, dated Dec. 4, was obtained by The Associated Press.

Duane D. Fitzgerald, president and chief operating officer of Bath Iron Works, called the bailout suggestion ''laughable.'' He said the Navy and the company did agree on contract adjustments, but they totaled $35 million.

The Navy denied that a bailout took place and stressed that the ships, hailed as the most advanced combat ships ever, will be built within budget.

Bennett, in a two-paragraph statement released late Wednesday, said he received Dingell's letter, which ''makes many assertions and raises many questions of fact.''

''The Navy tells me today that some of this information is incorrect, and that some of the letter's conclusions are unjustified,'' said Bennett, who cautioned against jumping to conclusions but promised a subcommittee inquiry into the destroyer program when Congress returns in January.

The DDG-51 destroyer, named after Arleigh Burke, World War II naval hero and former chief of naval operations, is designed with a more expensive all- steel superstructure instead of one that was part aluminum and more prone to splintering and fire damage.

The first destroyer, which is scheduled to be delivered to the Navy in February 1991, will be equipped with sophisticated Aegis computers and Tomahawk cruise missiles.

The Navy has tried to reduce the destroyer's radar cross-section, which is the enemy's ability to discern the type of ship showing up on radar, and give it some of the characteristics of the Air Force's B-2 stealth bomber.

The steps taken by the Navy to reduce the radar cross-section of the new destroyer include ''more rounded edges and less 90-degree angles. ... A reduction in cross-section means an enemy has to get in closer,'' Cole said. The same approach was taken with the B-2.

Dingell contends that incorporating stealth characteristics on an 8,315-ton all-steel ship became an overwhelming design and engineering problem for Bath Iron Works that led to the contract increases.

Dingell also said that ''according to experts, an airborne radar at an altitude of 50,000 feet would detect it easily at over 300 miles.''

Complicating the situation is the number of Soviet anti-radiation missiles that can be air-launched, ship-launched or submarine-launched, said Dingell, who cited a secret report by the Defense Intelligence Agency and Central Intelligence Agency titled, ''Special Assessment on the Anti-Radiation Missile Threat.''

Fitzgerald questioned the appropriateness of Dingell's references to a classified issue such as naval radar capability.

''The whole business of radar signature still has same classifications. Congressman Dingell can choose to violate his security clearance. I don't choose to violate mine,'' Fitzgerald said.

''Suffice it to say we think he's wrong,'' the executive added.