New Kids Will Interrupt Tour to Prove That They Do Sing : Pop music: The teen heroes will appear live on ‘The Arsenio Hall Show’ Wednesday to counter lip-syncing charges.

Pop teen heroes the New Kids on the Block will interrupt their Australian tour to perform live Wednesday on “The Arsenio Hall Show” in Los Angeles to counter charges made this week by their former musical director that the group lip-syncs in concert and contributed less than 30% of the singing on their records.

The group was sued Jan. 24 for creative infringement and breach of contract by Gregory McPherson, a University of Massachusetts professor whom they employed as a music director and producer from December, 1988, through December, 1990. The suit, filed in Suffolk Superior Court in Boston, seeks $21 million for creative contributions and royalties.

McPherson also claims that the New Kids’ singing has been masked on record by voice-overs created by Maurice Starr, the Kids’ manager, and his brother Michael Johnson. Both men and the New Kids deny the charges.

“We believe that by performing live on Arsenio’s show, it will give us the opportunity to prove to anyone who doubts us exactly what we can do,” the New Kids said in a statement released Friday by their Los Angeles publicist. “It will enable us to disprove accusations made about our vocal abilities by this disgruntled former employee.”

McPherson said he believes a performance on Hall’s show will do little to restore the group’s credibility.

“What kind of proof is that,” McPherson said in phone interview Friday from Boston. “I did an Arsenio show with them in 1989 where they sang along with a synthesizer sample of the singing from the album.

“I know Arsenio likes to think his show features live performers, but that’s not always the case. All you have to do is watch a tape of that (1989) show and you can see what’s happening.”

An audio technician for Hall’s show who was on the set during the taping of the New Kids 1989 performance disputed McPherson’s charges.

“There were five microphones that night and all the guys were all singing,” said Barton Michael Chiate, who helps produce the musical segments for the show. “If you listen to the tape, it’s very rough. It was obviously their voices.”

The Boston-based Kids were the nation’s highest-paid entertainers, according to a Forbes magazine calculation last fall, which estimated that they earned $115 million in 1990 and 1991.