The wife of South Africa's intelligence minister was convicted on Thursday of drug trafficking for using young women as mules to smuggle cocaine into the country.

Sheryl Cwele, who is married to state security minister Siyabonga Cwele, was convicted along with Nigerian Frank Nabolisa in the High Court in the eastern city of Pietermaritzburg. Both had pleaded not guilty.

Judge Piet Koen said the two had clearly worked together to recruit two women as drug mules, according to the Sapa news agency.

The verdict had originally been expected on Wednesday, but was delayed after prosecutors sought to introduce new evidence, which the judge refused.

Cwele was arrested in January 2010 and has been out on bail. Sentencing was set for Friday, when the pair face minimum jail terms of 15 years.

Allegations of Cwele's drug trafficking surfaced in 2009 after the arrest of Tessa Beetge, a South African woman caught in Brazil with 10 kilos of cocaine worth almost $300,000 (202,000 euros).

Beetge's parents told a South African newspaper that Cwele, a former neighbour, had arranged their daughter's trip to Brazil after offering her a job overseas.

Beetge is currently serving an eight-year jail sentence in Sao Paulo.

The other woman, Charmaine Moss, was hired to collect an unspecified parcel in Turkey. She suspected foul play, declined the offer, and turned state witness.

Cwele's arrest has led to opposition calls for her husband's resignation. He was not at court for the verdict, and his office said no statement would be issued on the case.

Cwele, a municipal director of health and community services, has argued that she met Nabolisa through an acquaintance and agreed to help him recruit two white people to work for his company.

She had promised the women 25,000 rands ($3,700, 2,500 euros) for two weeks of work abroad.

In his ruling, Koen said that Cwele was deeply involved in travel arrangements for the women, and questioned the high payment offered for work that required no qualifications.

"Why would she be so concerned with travel arrangements if she was not involved?" he said.

The conviction is the latest stain on South Africa's security services, after the police's crime intelligence chief was arrested in March over a deadly love triangle a decade earlier.

Lieutenant-general Richard Mdluli spent days on the run before turning himself in.

Mdluli is seen as close to Jackie Selebi, the former police boss convicted of corruption for accepting more than 1.2 million rands ($177,000, 123,000 euros) in bribes from organised crime between 2000 and 2005.

Police are also embroiled in a series of scandals over brutality against protesters and corruption in contracts.

Cwele's conviction is likely to raise questions about the integrity of her husband's work, said Johan Burger, a crime analyst at the Institute for Security Studies.

"The judgement is likely to impact on the position of her husband, who heads a very critical government portfolio," Burger said.

"I think government also needs to look at how she might have abused the position of her husband to access secret information she may have used in her activities," he added.