The government was looking at re-prioritising its spending to find an extra R5-billion it needed to pay for salary hikes for striking public service workers.

"We have not taken a decision yet in terms of where we are going to cut to get the R5-billion," Public Service and Administration Minister Richard Baloyi said in a media briefing in Cape Town on Wednesday.

"We are not hiding anything. Where we are, having tabled our offer of 7% salary increment plus R700 housing will require R5-billion additional to cater for that," he said.

"But definitely to get the R5-billion, we are going to have to re-prioritise somewhere."

Baloyi said that the government's offer was now a draft resolution of the Public Service Coordinating Bargaining Council and that he had instructed his director-general to sign it by 10am on Thursday.

"Having done all it takes, as government as the employer, you can't keep negotiating," he said.

"Tomorrow in Pretoria, before 10am I've instructed the director-general that all I expect is nothing less than his ink dripping on paper signing that offer."

The Congress of South African Trade Unions (Cosatu) and the Independent Labour Caucus (ILC) announced on Tuesday that "the strike is on" after their members rejected government's offer of a 7% salary increase and a R700 monthly housing allowance.

The unions wanted an 8,6% increase and R1 000 monthly allowance.

But Baloyi said that the government had "exhausted" its capacity for further increases and appealed to the unions to "let sanity prevail".

"As government, we have demonstrated for all to see that our capacity to afford is exhausted," he said.

"If you talk of an envelope, we have not emptied it. We have broken it. We want to make a call to South Africans, to our leaders, to our public servants who are members of these unions not to pressurise their leaders."

The offer will be on the table for 21 days, Baloyi said, after which the government will "have to implement".

"We will continue to engage so that we make sure that the signing becomes a reality."

He realised that some might think for the government to implement the offer might be unilateral. He challenged that thought, however. "It is not a final position out of choice. It is a final position out of affordability."

Baloyi said that the government would not tolerate anarchy by striking workers and that it was ready to "deploy forces" to counter intimidation.

"As government we will make sure we will deploy our forces that are ready to manage the situation to make sure that no intimidation takes place," he said.

"People should not be talking war slogans. We are not in a war situation."

Thousands of nurses, teachers and other public workers stayed away from work on Wednesday, with unions claiming the strike will escalate.

The 200 000-strong Public Servants Association (PSA) said it would join Cosatu unions in a national strike on Thursday.