Jacob Zuma and Bulelani Ngcuka are two of the country's most powerful figures, and they are set on a collision course which has seen an increasingly vicious dirty-tricks campaign being fought in the public arena.

This weekend that "smear campaign" - as both camps have called it - rose to new heights.

Rumours of Ngcuka's imminent resignation did the rounds in political circles, and reports surfaced that his luxury BMW had been seized by the government. Both proved to be false.

A Sunday newspaper led with the headline "Govt grabs Ngcuka's luxury BMW - Scorpions boss feels the squeeze".

Sipho Ngwema, Ngcuka's spokesperson, said "the forces behind the smear campaign" against Ngcuka were "getting desperate" and that the story was "distorted".

City Press reported on Sunday that the government had ordered Ngcuka to surrender his luxury BMW on the grounds that his contract did not entitle him to a car allowance.

The justice ministry conceded that the issue dated back to 1998 and said there was "no substance" to the report.

Ngwema said the rumour about Ngcuka's car confirmed Ngcuka's earlier claim that there was a whispering campaign against him.

Talk about Ngcuka resigning was laughable. "There's no truth to that rumour," he said.

Justice ministry spokesperson Paul Setsetse said there was "no dispute about Mr Ngcuka's car", and suggested there was mischief involved.

There had been an "administrative error" on the government's part regarding Ngcuka's car allowance which dated back to 1998.

While it was true that Ngcuka owed the department money relating to his BMW, there was nothing untoward about the matter.

"We have not invoiced him (Ngcuka) yet... and there's no dispute about it.

"Whoever is putting these things in the media is being malicious because there is no substance to what they are alleging," Setsetse added.

Political analyst Steven Friedman, of the Centre for Policy Studies, said he believed that the whispering campaign would have the effect of eroding public confidence in the country's political system.

With acknowledgements to Jeremy Michaels and The Star.