About 180,000 workers in South Africa's public service sector will strike on July 29 after wage negotiations with the government became deadlocked, a union official said on Thursday.

"We have been issued a certificate to strike and the strike may be much larger if COSATU-affiliated unions join us," said Public Servants Association spokesperson Manie De Clercq.

State workers including nurses, teachers, policemen and immigration officers rejected the government's 6.5 percent wage offer and are demanding an 8.6 percent increase as well as a 1,000 rand ($130) monthly housing allowance.

The strike could hurt the economy as it recovers from its first recession in 17 years.

Salary negotiations with the country's largest labour umbrella group, the Congress of South Africa Trade Unions (COSATU) have also become deadlocked and the federation is balloting its members on whether to join the strike.

"We hoping that the employer will revise its offer but in the event that they don't, we will also strike by next week," said Sizwe Pamla, spokesman for the National Education, Health and Allied Workers -- a COSATU affiliated union.

If COSATU joins the industrial action, about as many as 1.3 million state employees could walk off their jobs.

Reuters