A lawyer for more than 60 suspected South African mercenaries jailed in Zimbabwe for their involvement in a coup plot in oil-rich Equatorial Guinea says they may return to South Africa on Saturday.

The year long saga of a suspected coup plot in Equatorial Guinea is drawing to a close as a group of South Africans' prison sentences are reduced by four months following an appeal to the country's second highest court.

Back home in South Africa, they face charges under the country's anti-mercenary legislation. But lawyers say they are likely to negotiate a plea bargain and be instantly released.

According to South Africa and Equatorial Guinea, the men had planned to fly to Malabo, overthrow the government and install an exiled opposition leader.

Among the alleged plotters was British businessman Mark Thatcher, son of former British Prime Minister Margaret Thatcher. He was accused of partially financing the alleged plot and was recently fined $500,000 by a South African court for violating its anti-mercenary laws.

The group's alleged ringleader, former British army officer Simon Mann still has four years of his sentence to serve in Zimbabwe's maximum security prison on the outskirts of Harare.

His lawyer Jonathan Samkange has hinted he might get a presidential pardon around the time local elections are held at the end of the month. South African and Equatorial Guinean prosecutors want to try him for the alleged coup attempt.

In Equatorial Guinea, a more than a dozen South Africans and Armenians are serving long prison sentences for their role in the alleged plot.

The men detained in Harare had flown in from South Africa to collect weapons bought from the Zimbabwe government's defense industries.

South African intelligence operatives had tipped off Zimbabwean security forces who arrested the men. They claimed they were on their way to guard a mine in the Democratic Republic of Congo.

The men were tried and pled guilty to relatively minor immigration and firearms charges. The state had no evidence to connect them to the alleged plot in Equatorial Guinea. Zimbabwe has no legislation to prevent mercenary activities.

Attorney Alwyn Griebenow, who represents the men in Harare waiting to be released, says they could be home on Saturday.

He says he is not sure why they have not already been released because all the documentation is complete. He also said he is not sure if they are sent to the airport Saturday whether there will be any seats available on a flight to Johannesburg.