user: Problem: Unions affiliated with Cosatu, South Africa's main union federation, have been holding out for an 8.6% rise, more than the latest government offer of 7%.
The strike was reported to have got off to a slow start, though unions say more than a million people could take part.
Many schools, hospitals and public offices are expected to be affected.
Police, teachers, doctors, and nurses are demanding an above-inflation 8.6% pay rise, improved housing subsidies, and other benefits.
But South Africa's government says it can barely afford the 7% offer it has put on the table.
The government needs to find 5bn rand (Â£440m; $687m) and will have to "re-prioritise" its plans for the year to fund their offer, the minister in charge of the public sector has said.
"It is not the final offer of choice, it is the final offer out of affordability," Minister for Public Service and Administration Richard Baloyi told reporters at the Parliament in Cape Town.
Last week, tens of thousands of public sector workers staged marches to hand over their demands to authorities.
By Pumza FihlaniBBC News, Johannesburg
In a strike that threatens to cripple South Africa's economy, eyes will be glued on President Jacob Zuma.
Many hope he will provide a clear plan of action from the government, and most importantly a sense that he is in control.
This will not be an easy task. Mr Zuma owes his rise to the presidency largely to Cosatu's backing. This perhaps explains why the federation feels entitled to demand an increase which is almost double the inflation rate.
Unions say they are tired of being "paid peanuts" while politicians, including Mr Zuma, live lavishly.
It will be a case of who blinks first in this face-off as both sides have taken a hard line.
The government says "our offer is final" while the unions insist "we will not compromise"- so how will Mr Zuma defuse the situation?
The coalition of unions represents an estimated 1.3 million public sector workers, including government bureaucrats and judicial officials.
A spokesman for Cosatu was quoted as saying that 90% of those workers could take part.
The union grouping said its members planned to hold marches outside branch offices throughout the country, culminating in a national march on 26 August.
"We made it clear to the employer that our members were resolute in their pursuit of the original demands," Cosatu said in a statement.
It is difficult to gauge the national impact of the first day of the strike but the BBC's Nomsa Maseko reports from the Natalspruit Hospital east of Johannesburg that nurses there refused to work, turning away scores of patients.
In a show of defiance some 200 workers marched inside the hospital wards chanting songs, and patients said they went without food, medicine and cleaning the whole day due to the strike.
The hospital is now discussing calling in army medics until the situation returns to normal, while patients in a critical condition would be transferred to nearby hospitals not affected by the protests.
Unions representing teachers and nurses were the first to announce that they would join the strike following negotiations late on Tuesday.
"From tomorrow there will be a total shutdown and the beginning of a protracted strike and we will only stop when government responds," said Thobile Ntola, head of the SADTU teachers' union.
The government has been urging children to come to school, but many pupils were expected to stay away on Wednesday, having been told not to turn up by their teachers.
Minimal health and policing services were expected to keep running, with employees deemed to be essential forbidden from taking part in strikes.
South African schools have already been hit by spontaneous walk-outs this week, and there have been reports of intimidation and violence being used to keep people away from schools.
South Africa has seen a wave of strikes in recent years, though unions have warned that the latest one could be the largest for several years because it is indefinite.
Analysts say President Jacob Zuma, who owes his political support to South Africa's powerful trade unions, is under pressure to appease them while also addressing the country's budget deficit.
What was that article about?

A: Public sector workers in South Africa have begun an open-ended strike, having rejected the government's offer of a pay rise.

Problem: The 29-year-old's 18th-minute dismissal was his second red card of the season.
The former Kidderminster man was also banned for the first eight games of this term, after an alleged bite on an opponent during the previous campaign.
Cheltenham are 18th in League Two, seven points above the relegation zone.
What was that article about?

A: Cheltenham Town midfielder Kyle Storer has been banned for four games after the club's appeal against the red card he received in Saturday's 0-0 draw with Mansfield in League Two was rejected.

Problem: The 23-year-old has been handed a 12-month contract at Bet Butler Stadium.
Campbell, capped for Scotland at under-19 level, will continue in the Scottish Championship after experiencing relegation with Morton last season.
He had spent three years at Cappielow after his release by Rangers and scored five goals in 35 appearances last season.
Campbell also spent time on loan to Cowdenbeath while under contract at Ibrox.
He becomes Sons manager Ian Murray's fourth signing of the summer.
Midfielder Scott Taggart has also switched from Morton, while Murray has recruited two defenders released by Premiership clubs - David van Zanten, who was with St Mirren, and Lee Mair, previously with Partick Thistle.
What was that article about?

A:

assistant: Dumbarton have signed Archie Campbell after the former Rangers and Greenock Morton striker impressed on trial.