By Barnaby Phillips BBC, Johannesburg

"Robert Mugabe Must Go!" chant the Zimbabwean exiles demonstrating on the streets of Johannesburg.

They are calling on countries to show their abhorrence of President Mugabe's policies by boycotting next month's World Cup cricket matches.

Jay Jay Sibanda fled Zimbabwe last year.

He says it is wrong to play sport when people are being tortured by their government.

"Sport is having fun, it's enjoying. But just a few meters away from where the few people are having fun, someone is starving, someone is being tortured, someone is getting killed, at the hands of the government.

"It's not fair that we have this game in Zimbabwe," he says.

'Inappropriate'

In fact most of the World Cup games will be held in South Africa.

But six teams are scheduled to travel to Zimbabwe.

Whatever is happening politically, why not let people enjoy their sports in Zimbabwe?" South African man

Ali Bacher, the South African chief executive of the World Cup says any team that refuses to go to Zimbabwe will be penalised.

And Dr Bacher says it is for governments - not cricket authorities - to decide whether there should be a boycott.

"You cannot ask, and it's inappropriate to ask a cricketing body to make a very significant political decision of this magnitude," he said.

"In my opinion, this should be the sole domain of the respective governments".

Financial lifeline

Zimbabwe and sport are two highly emotive subjects in South Africa, so it is not surprising that the World Cup row is arousing strong feelings.

In a plush mall in Johannesburg's northern suburbs, I found a majority opposed to allowing Zimbabwe to host any games.

Some players have said they will go if allowed

"No way should they play cricket there, not with a dictator like Robert Mugabe," said one man.

A woman agreed: " I think cricket should be held in a free country where there is democracy and all people are treated alike".

But another man said: "Sports is sports. Whatever is happening politically, why not let people enjoy their sports in Zimbabwe?"

And, not surprisingly, that is the argument of the Zimbabwean Cricket Union (ZCU), for whom the World Cup represents a financial lifeline.

ZCU head Peter Chingoka argues that politics and sport should be kept separate from each other.

"It is important that the cricketers, black and white, continue with the World Cup as it is not fair to ask them to suspend their careers just because you want to bring in political issues into the matter," he told the BBC.

No consensus

But in this part of the world, sports and politics have long been entwined.

The sporting boycott against the old apartheid regime helped play an important role in isolating the South African Government in the 1970s and 1980s.

The difference this time is that there is no international consensus on what action to take against Zimbabwe.

If England, and possibly Australia, do decide to boycott their games in Harare and Bulawayo, they should not expect any other countries to join them.