About 99 percent of all private household employees, mainly domestic workers, are employed informally, meaning they have no formal employment contracts.
This is according to the latest labour force survey report released by Stats SA yesterday.
Stats SA said workers who are employed informally have no entitlement to medical aid or pension plans from their employers, and might not have a written contract of employment.
In the second quarter of 2008 the construction industry had the second highest percentage of people employed informally - amounting to 54,8 percent.
During the same period the agriculture industry had the third highest percentage of people in informal employment, accounting for about 50,1 percent of its labour force.
Kevin Lings, an economist at Stanlib, said: "The labour market will come under pressure, including the informal sectors. Generally businesses and informal employers might try to work with temporary staff as it might improve flexibility.
"This is because companies don't want to end up with a lot of permanent staff, especially in current economic conditions."
Jaco Kleynhans, spokesman for trade union Solidarity, said that this was an indication of poor quality jobs.
"The quality of jobs is a determining factor of the general quality of people's lives," Kleynhans said.
"All the people in so-called informal employment work extremely hard and also for long hours.
"It is important that the quality of jobs created must give better rewards than social grants."
The trade and private households industries together account for more than 2,5 million of the 4,9million employed in informal employment.
Dennis George, general secretary of Fedusa, said: "We agreed with the department of Labour that the wages of domestic workers should increase with an inflation rate plus 2 percent.
"Unfortunately the same is not happening with agriculture and construction workers."