The South African Democratic Teachers Union (Sadtu) and the National Professional Teachers Organisation of South Africa (Naptosa), which together represent more than 100,000 teachers, have turned down an offer of 5 per cent and are demanding 18.4 per cent.
Teachers say the offer is too low to combat inflation which is currently more than 10 per cent.
Both teacher unions have declared a dispute with government, and Sadtu (with a mainly black membership) has embarked on mass action, including marches this month by nearly 60,000 teachers around the country.
Minister of education, Sibusiso Bengu criticised SADTU for resorting to mass marches while still negotiations were still under way.
Earlier, the government had proposed borrowing funds from the national teachers' pension scheme to boost salaries. Both Sadtu and Naptosa initially rejected the proposal because of concerns that teachers might not get their full pensions on retirement.
On May 18 the parties met again, and after assurances that pensions would not be affected, Sadtu accepted the offer of borrowing money but Naptosa rejected the proposal.
Sadtu has accused Naptosa of opposing restructuring of the previous apartheid system.