Florence Simfukwe of Hyattsville was at work when the bad news came in a telephone call from a family friend: Her parents, Orton and Vera Chirwa, are to be hanged for treason in their native country, the small African nation of Malawi.

"It's like I'm having a funeral without the bodies. I'm mourning," Simfukwe said of the sentence imposed on her father and stepmother, who are both highly educated lawyers and opponents of the one-party rule of Malawi's President for Life Hastings K. Banda.

The decision imposed May 5 by a Malawian court sent the 42-year-old widow into an emotional tailspin. Since that day, she has been unable to concentrate on her college courses and has felt "really depressed."

Simfukwe, who supports her three sons by working as a delivery room nurse at Columbia Hospital for Women, also fears that her youngest brother, Fumbani, 27, is dead. Detained by Malawian security police along with her parents on Christmas Eve 1981, he has not been seen or heard from since.

The Chirwas have appealed the death sentences.

A strong, articulate woman who talks with warmth and an earthy verve, Simfukwe has felt the toll of her parents' troubles. "I go back and forth between being mad and feeling sorry for myself," said Simfukwe, who sings in the choir of the Hyattsville Presbyterian Church, where she has found moral support.

Jack Carlson, pastor of the church, said he and many of his parishioners have asked U.S. congressmen to intercede and have written letters to Malawian officials "to bring our concern to the attention of the Malawian government." They have never received a reply from Malawi, he said.

Sens. Paul S. Sarbanes (D-Md.), Charles McC. Mathias Jr. (R-Md.) and Rep. Steny H. Hoyer (D-Md.) have all been in touch with the State Department to express their concern about the case, staff aides confirmed.

But State Department officials have said that there is little they can do beyond emphasizing to the Malawi government their concern that the Chirwas received due process of law.

The history of Orton Chirwa, 64, is intricately bound up with that of his country: The first black Malawian called to the British bar, he helped write Malawi's constitution and served as the country's first justice minister and attorney general. His wife, Vera, 51, is the country's first woman lawyer and they are both well known in international legal circles.

News of the death sentences shocked many lawyers and followers of African political developments, who say the sentence is unduly harsh for the alleged crimes. In addition, the lower court in which the Chirwas were tried does not "comply with international standards of due process," according to Niall MacDermot, secretary general of the Geneva-based International Commission of Jurists.

"Many years ago they set up traditional courts in Malawi to try criminal offenses. They were composed of chiefs without legal training and no lawyer has any right of appearance before the courts so the accused cannot be defended," said MacDermot, who knows Chirwa personally.

Trying a person for treason in one of the local courts rather than in the country's higher courts "is a little bit like trying someone for homicide in a District small claims court," said Jay Jacobson, a New York lawyer who was sent by the Kennedy administration to help the Malawians negotiate their independence from Britain and met Chirwa then.

Simfukwe said that her father began to oppose Banda, Malawi's first president, shortly after the country achieved its independence in 1964. That same year, after receiving death threats, he and his wife went into exile in neighboring Tanzania. In 1977 they set up the Malawi Freedom Movement, which published tracts criticizing Banda and calling for his overthrow. But by all accounts, the movement did not engage in violent activities.

Simfukwe came to the United States with her diplomat husband in 1971 when he was assigned to the Malawian Embassy here. But because of Simfukwe's family connections, her husband was so harassed by other embassy employes that he quit in 1972, she said. They were given permanent residence permits to remain in the United States and he made his living at odd jobs, Simfukwe said.

During a trip home to Malawi to visit relatives in 1977 they were both arrested and held for a week by Malawi police, Simfukwe said. While being interrogated about her father's activities, she said, they were refused food for a week. Her husband, who was on special medication after a kidney transplant, was denied his treatment. He died six months after they returned from Malawi.

In early 1982, Simfukwe received word from a sister living in Zambia, which borders on Malawi, that her parents and her brother had been kidnaped by Malawi security police. Malawi authorities deny this and say the Chirwas were arrested after they slipped into Malawi with the intention of overthrowing the government. Simfukwe says that as a wanted man, her father would not be "stupid" enough to enter Malawi.

The Chirwas were detained incommunicado until their trial, which began last July and resulted in conviction and the death sentence. They have appealed the sentence, but foreign observers point out that the appeals court of the traditional legal system also does not meet international standards of due process.

According to ICJ's MacDermot,"we know of no evidence presented at the trial which would amount to what we would call treasonable activity. In a democratic society it would be perfectly lawful." The ICJ, Amnesty International, the House subcommittee on Africa and the American Bar Association's International Law and Practice Section, have all made appeals to Banda for a commutation of the death sentence.

A State Department official said: "We are interested in making sure that the Chirwas receive due process of law under Malawian law and that's all we can really express an interest in . . . . We hope that this former colleague of President Banda and his wife will receive the full consideration of Malawian law and that their appeal will be heard."

He added that "up to this point we have no reason to question" that due process has been followed. Officials at the Embassy of Malawi declined to comment on the case.

Meanwhile, Simfukwe and her sons, who attend Riverdale Elementary School and Bladensburg High School, wait anxiously for news.

"I'm in mourning and yet they are not really dead, pyschologically it's really rough," Simfukwe said. "But I still believe that miracles do happen in this day and age. But knowing the way things happen in Malawi I'm dead scared, but I try to be optimistic because I believe in God. But it's the helplessness, being so far away here. I guess that's what's eating me."