About 100 000 contract cleaning workers may go on strike over wages, their industry chief negotiator for labour Lungile Ntshuntshe said on Monday.

"Our wage demand now stands at 15 percent, while employers would not budge off their 7.53 percent offers," Ntshuntshe said in a statement.

Negotiations between the trade unions representing workers and the employers, represented by the National Contract Cleaning Association and the Black Empowerment Cleaning Association, started in July.

The unions involved are the South African Transport and Allied Workers' Union, South African National Security Officers' Forum, South African Commercial, Catering and Allied Workers' Union and the Hotel, Liquor, Catering, Commercial and Allied Workers' Union of South Africa.

According to Ntshuntshe, when the two parties could not agree on salaries, a dispute was declared by the unions early in October.

"Employers have since agreed to an additional week's pay to the current annual bonus of three weeks. However, they have not made any offer on a number of other demands," said Ntshuntshe.

These include the introduction of one wage rate across all areas to replace the two-tier wage system of one rate for urban areas and another for smaller towns.

Workers also demanded a percentage increase on employers' provident fund contribution and that the employer should supplement the UIF maternity benefits to ensure that a full salary was received.

"We also demand the introduction of a basic weekly wage, to replace the hourly rate," he said.

Workers initially demanded 20 percent, but had since gone down to 15 percent

Ntshuntshe asked: "How can the current wage rate of R11.16 per hour be justified? How can the employers' revised wage offer of R12 per hour be acceptable when managers and owners, both black and white, earn more than R20 000 every month?"

He said employers were blaming their clients as the reason they could not improve working conditions in the sector.

"This is another form of labour broking, where 'agents' or contract cleaning companies make their profit by selling the cheap labour of their employees," Ntshuntshe said.

The unions have received a certificate of non resolution from the Commission for Conciliation, Mediation and Arbitration.

"We are now consulting our members about proceeding with strike action," he said, adding that it could be black Christmas for workers in the industry, majority of whom were single mothers.

The employers' associations could not be reached for comment.