Vietnam charged China yesterday with trying to sabotage its already troubled economy, apparently confirming reports that Peking has cut off at least some aid to Hanoi in retaliation for alleged persecution of ethnic Chinese.

Radio Hanoi, in what appeared to be its most direct attack on China in an escalating propaganda war, said the "slanderous propaganda" dispensed by Peking was designed to hurt Vietnam's effort to recover from the ravages of a long war.

"Sober-minded people can easily see that the aim is to cause difficulties to socialist construction in Vietnam," the official broadcast commentary said. "This is a serious move (designed to) sabotage the long freindship" between the two Communist nations.

The broadcast gave no details of how Vietnam's economy had been affected by China's attacks on Hanoi for forcing a mass exodus of ethnic Chinese across their mutual border, but diplomatic sources here, in Peking and in Hanoi have reported work on several Chinese-funded development projects in Vietnam has stopped.

Some diplomatic sources said the Chinese have told the Vietnamese they are withdrawing technical personnel and funds from 20 projects so that the money can be used to help feed, clothe and house the refugees that have flooded into southern China.

Communist sources here said China would complete work on projects that are well under way. Peking may wish to avoid appearing as callous as the Soviet Union did when it abruptly withdrew all support for Chinese development projects in the early 1960s, forcing the Chinese to spend years repairing the damage to their economic plan.

Peking's dispute with Moscow and its suspicions of Vietnamese ties with the Soviets have already appeared to limit its aid to its southern neighbor. After the Soviets agreed to a $2.5 billion aid program for Vietnam, China ended its donations of about 500,000 tons of rice a year and rejected Vietnamese requests to match the Soviet financial commitment.

Economists here estimate, however, that Chinese aid to Hanoi may still be as high as $300 million a year, much of that used to finance rice imports to meet Vietnam's current food shortage.

Meanwhile, a leading newspaper here with links to Peking chided Hanoi yesterday for delaying the evacuation of Chinese refugees from Vietnam and suggested that Soviet warships were maneuvering in the South China Sea to aggravate the situation.

Hanoi, in the meantime, continued to counter Peking's charges of persecution of Chinese living in Vietnam.The official Vietnam News Agency reported several statements of support for the Hanoi government from ethnic Chinese in both parts of Vietnam.

"My family and myself are not discriminated againt in any way," said 22-year-old textile mill worker Chau Nguyet Anh, whose brother had fought in the U.S backed South Vietnamese Army. Some Chinese quoted by the agency said relatives who had fled to China recently were returing.

News agencies reported yesterday from Hong Kong:

A Paris-based Chase Manhattan Bank executive made a secret trip to Hanoi last month and met with top Vietnamese officials to discuss normalization of relations with the United States.

Ridgway Brewster Knight, a former American diplomat and now Chase Manhattan's director of international relations in Europe, reportedly spent a week in Vietnam and returned with a personal message for President Carter that contained several suggestions for relaxing U.S trade restrictions against Vietnam.

A bank spokesman in New York confirmed that Knight made a trip to Hanoi late last month, but described it as "exploratory, and on bank business."