More than a million government workers have staged a crippling one-day strike in South Africa, bringing public service to a virtual standstill in parts of the country.

Thousands of civil servants marched through Pretoria and Cape Town on Tuesday as part of a "total
shut-down of the public service" aimed at increasing pressure on the government of Jacob Zuma, the South African president, over better salaries.

The strike was also aimed at prompting the government to reach a deal by a Thursday deadline set by the unions.

Zwelinzima Vavi, general secretary of Cosatu, the largest umbrella labour organisation in the country said "we are asking for 8.6 per cent only".

"We are asking for a mere 1000 rands for a housing allowance only. This is peanuts, comrades," Vavi told workers in Cape Town.

"We have spoken to them for the past seven months, they are not listening, they are not listening. Today, this is not a strike, we are only firing the first warning shot."

Pay raise dispute

Unions are calling for an 8.6 per cent pay hike, twice the current rate of inflation, and a 1,000 rand ($138) monthly housing allowance.

The South African government is offering a seven per cent pay hike and 630 rand for housing.

However, it is likely to raise its offer rather than risk a walk-out that could prompt a prolonged public sector strike reminiscent of a 2007 strike that dented the economy and damaged support for Zuma's predecessor.

Experts predict the ruling African National Congress (ANC), in a long-standing alliance with Cosatu and the South African Communist Party (SACP), will give in to the unions' demands.

Tuesday's strike affected schools and public offices, but essential services such as police and hospitals were running, albeit on reduced staffing.

A mid-grade public sector employee makes on average 8,800 rand a month in salary and benefits, above the national average wage of 6,383 rand, according to government figures.