A Virginia medical examiner said yesterday internal injuries that a political activist fighting South Africa's apartheid system said he received in a beating by two masked men were not caused by such an assault.

Dr. Faruk B. Presswalla chief police medical examiner for the Tidewater area, said there is no evidence to support the claim by Richard E. Lapchick that internal bleeding kidney or liver damage or a recent hernia were caused by the beating.

Presswalla's latest assertion followed an earlier disclosure that in the medical examiner's opinion the misspelled word "niger" that Lapchick said was carved on his stomach with a pair of scissors by his assailants was self-inflicted.

Lapchick and one of two doctors who examined him at a Virginia Beach hospital disputed Presswalla's findings.

"I absolutely didn't do it," said Lapchick, a 32 year-old professor at Virginia Wesleyan College. He said he was shocked by Presswalla's conclusions."His conclusions contradict those of the doctors who cared for me in the hospital."

Dr. D. C. Amarasinghe a general and vascular surgeon who treated Lapchick, said, "He (Lapchick) did have some evidence of internal injuries . . . They're unlikely to be self-inflicted."

Presswalla, who examined Lapchick two days after the alleged assault, said, "I'm not saying that he wasn't assaulted, but there are some medical inconsistencies."

He said he believes the carved word "niger" was a self-inflicted wound because of the manner in which it was written. "It's written with squared letters of equal size and equal distance apart in horizontal straight lines with each letter having multiple strokes." He said the "i" was dotted.

The medical examiner said the multiple strokes, called "hesitation marks," are normally found on self-inflicted wounds. "It's not the type of thing that a person assaulting another person would do." He said such a wound from an assault would be scratched and would not contain square letters nor traces "one on another."

He also said a hernia that Lapchick claimed was a result of the beating was an injury that the college professor had before the attack. "It was an antecedent. It was not related to the assault," Presswalla said.

Dr. Martin Lorenz, an emergency room doctor who treated Lapchick after the assault, told a Norfolk newspaper he found microscopic traces of blood in Lapchick's urine, which could have been caused by blows to the kidney. However, he said medical tests showed no serious kidney damage.He also said a liver scan procedure showed some possible minor liver damage, but that the test was inconclusive.

Lorenz refused to comment yesterday on whether the injuries were self-inflicted.

Presswalla said he has recommended to Lapchick that he submit to a polygraph test. Lapchick has refused.

Lapchick said he declined to take the lie detector test, saying the police have 'uncontroverted evidence' of the seriousness of the assault, and the two doctors who examined him at the hospital found it was impossible that the wounds could be self-inflicted.

"It seems as if each time I begin to recover from the physical beating I received on Feb. 14, the people representing the system of justice strike harder and deeper blows," Lapchick declared. "I can only feel that this request made of me arises out of the traditional trend displayed by law enforcement authorities in doubting those who are willing to take a stand on civil rights issues."

A Virginia Beach police detective said the matter is still under investigation.