South Africa's Home Affairs Minister Nosiviwe Mapisa-Nqakula on Thursday vowed strong action, including deportation, against African migrants displaced by a wave of xenophobic attacks in May following a riot at a refugee camp outside Johannesburg.

'The time has come to put our authority in place,' the minister said in an interview with SAfm public radio, threatening to deport migrants who had applied for - but had not yet been granted - asylum, if they were involved in acts of violence.

While insisting 'we are a government that cares,' Mapisa-Nqakula accused migrants at a troubled camp in southern Johannesburg of trying to 'blackmail' the government.

Her statements followed a standoff between police and migrants at Glenanda camp, where 1,800 people are sheltering following a two-week orgy of xenophobic violence in South Africa in May, in which over 60 African migrants were killed.

Some migrants at the camp held security guards hostage overnight and barred food deliveries, according to the minister.

'These people are behaving in a manner which is unacceptable to the republic,' she said.

SAPA news agency reported that police, who arrived to free the security guards, had fired rubber bullets at the migrants, who allegedly refused to release the guards and threw stones at the officers.

A churchman at the camp told SAPA the residents had locked up the guards because they were traumatized and thought they might be spies.

The flare-up comes amid growing unease among residents of the government-run camps about their fate.

Several thousand migrants from countries including Zimbabwe, Mozambique and Democratic Republic of Congo, most of whom had been living in South Africa illegally, are living in camps around Johannesburg and Cape Town after being chased out of their communities.

The government has vowed to close the camps by August, despite many of the migrants expressing fear at returning to their communities.

At the outset of the xenophobic attacks, the minister had vowed not to deport affected migrants.