Five members of Bishop Abel Muzorewa's minority political party were shot and killed Sunday by supporters of Zimbabwe's ruling party, bringing to nine the number of reported deaths during the worst weekend of violence so far in this year's national election campaign.

The government said today that police in Hwange in the northwest had arrested two persons "suspected of being government supporters" in connection with the murders.

The five victims, three women and two men, all officials of Muzorewa's United African National Council, were pulled off a train Sunday following a political meeting in the town and shot, according to a witness who spoke at a press conference today.

At the press conference, Muzorewa said he held Prime Minister Robert Mugabe's government and the ruling Zimbabwe African National Union "directly and solely responsible for the murders." He called the killings "a climax of all the evil and wicked violence . . . which the ruling party has unleashed against the people of Zimbabwe."

Muzorewa, a Methodist clergyman who was prime minister during an interim government six years ago, also charged that Mugabe supporters destroyed at least 39 houses of his followers in Harare and abducted 14 people from rural Zvimba, about 40 miles west of Harare.

The government statement, released after a Cabinet meeting, appeared to be an attempt to head off charges that officials either instigated or condoned the killings. It said the incident would be fully investigated, and a spokesman said the law would "take its normal course." He noted that the government was making no effort to conceal the political leanings of the suspects.

The murders climaxed a weekend of political unrest. At least four persons were reported killed during street fighting between supporters of Mugabe and of opposition leader Joshua Nkomo after political rallies in Bulawayo, Nkomo's political stronghold.

According to reports from the semiofficial press here, two of those killed were ruling party officials who died when their car was stoned by Nkomo supporters. Two others, said by observers to be Nkomo supporters, allegedly were beaten to death.

The violence follows last week's government announcement that the elections, originally scheduled for March, were being postponed until June due to problems in registering voters and redrawing parliamentary districts. Many observers here, including western diplomats, fear the delay will aggravate tensions and lead to more deaths.

The incidents have also fed doubts that any poll held in the present political atmosphere can meet Mugabe's stated goal of being "free and fair." In recent weeks Nkomo has been unable to hold rallies anywhere outside the Bulawayo area due to violence by Mugabe supporters.

Although there are no official figures, reports indicate at least two dozen people have died during the past three months in political violence. The semiofficial Harare Herald today said seven members of the ruling party, including the two killed in Bulawayo last weekend, had been murdered and 11 abducted by "bandits" in the past 12 days.