The National Education, Health and Allied Workers' Union (Nehawu) vowed on Monday to embark on a strike if there was no agreement in the next round of public service wage talks.
"We are not threatening, we are promising. If there is no agreement we will have a strike," Nehawu president Vusi Nhlapo told reporters in Johannesburg.
The government is offering a six percent across-the-board wage increase, while the union is demanding between zero and 16 percent on a sliding scale.
Thousands of public servants went on strike and took to the streets last year when the government refused to meet their wage-increase demands.
Nhlapo said that if the government implemented the wage increase unilaterally, as it did last year, this would lead to a downfall of collective bargaining in the public sector.
He said that the outcome of wage negotiations this year would be determined by the strength of labour and that was the reason for the government not meeting the demands of the unions in 1999 because not all of its members took part in the strike action.
"We thought (last year) we could get the government to turn around, but this time all of the forces will be used ... Nehawu alone can bring the government to its senses."
The union's general secretary, Fikile Majola, said that the strike was also aimed at forcing the government to abandon plans to amend the conditions of service of public servants.
Majola said that Nehawu also wanted the government to stop plans to outsource certain government services. Recent studies had indicated that the service was not bloated as the government had suggested.
Nhlapo said that if his union did go on strike, it would have the support of other public service unions.
"The other unions are also unhappy."
On the upcoming local elections, Nhlapo said his union would support the African National Congress in the upcoming local government elections.
However, he said he was concerned over some of the ANC, South African Communist Party and Congress of South Africa Trade Union councillors who had not helped in "inspiring the confidence of our communities".
"We are concerned that the alliance, even at this late hour, has not found an agreed way forward with regard to the approach to the local government elections," Nhlapo said.
He said the union was also "deeply" concerned about the recent conflicts in the alliance.
Members of the SACP and Cosatu have over the past few days reiterated their criticism of the government's labour and economic policies.
Nhlapo said that an urgent consensus was needed among alliance structures.
On the Cosatu National Congress in September, Nhlapo said that the congress should not be pre-occupied with electing new leadership.
"We believe that ample time needs to be given to debates on policy issues rather than on tussles for leadership positions. In this regard we will play our role in attempts to find consensus around leadership and thus minimise the time spent on questions of leadership."
In this regard, the union's national executive committee decided at the weekend that all Nehawu national office bearers would not contest leadership positions at the congress.
Nehawu has 240 000 members and there are 1,1 million public servants.
The next round of wage negotiations is scheduled for Thursday and Friday. - Sapa