Harare - The head of Zimbabwe's national labour movement, detained for four days for holding an "illegal meeting," has been freed after a magistrate told police they had no right to interfere with union business, lawyers said Friday.

Lovemore Matombo and four other officials of the Zimbabwe Congress of Trade Unions were arrested in the north-western resort of Victoria Falls on Sunday while addressing union members.

They were accused of holding a meeting without police permission.

After long delays, they were finally brought to court in Victoria Falls on Thursday, where police demanded that they be refused bail.

However, magistrate Richard Ramaboea dismissed their request, and said laws restricting public meetings specifically exempted unions from having to obtain police approval, said lawyer Kucaca Pulu.

"He said the ZCTU is allowed to continue its meetings in fulfilment of its mandate," he said. "This is an embarrassment for the police.

The arrest of the unionists follows a string of arrests and detentions of opponents of President Robert Mugabe's Zanu-PF party in the last month.

These included the detention of two top officials from a umbrella body for non-governmental agencies, the abduction and alleged torture by state security agents of a transport official from Prime Minister Morgan Tsvangirai's Movement for Democratic Change (MDC).

Human rights organisations also report incidents of violence carried out by militias linked to Mugabe's Zanu-PF party in rural areas, which harken to last year's campaign of election violence.

The renewal of repression follows nine months of relative calm and stability under the coalition government formed by Zanu-PF and the MDC.

The ZCTU officials were arrested despite being in possession of a copy of the act exempting unions from state security laws and a court order, Pulu said.

"The leadership of the police feel they are above the law," he said.

In 2007, Matombo and other ZCTU officials were seized in a demonstration and subjected to prolonged assault by police with long wooden rods.

Mugabe at the time endorsed the police violence, saying police had a right to "bash" protestors who resist them. (dpa)