South African trade union Nehawu, one of the country’s largest public-sector unions, said on Friday that current wage agreements were sacrosanct and not open for review.

Nehawu’s comments come after President Cyril Ramaphosa said his government was speaking to unions about measures to contain the public sector wage bill.

The wage bill is a key worry for rating agencies since it accounts for around a third of consolidated government expenditure.

Nehawu is one of the largest affiliates of the Cosatu trade union federation that is in a ruling alliance with Ramaphosa’s African National Congress (ANC) party, so its comments carry weight in ANC circles.

“We note that the president stated that government is engaged with unions on reducing spending. … These discussions are not collective bargaining engagements on the salaries and conditions of service – we would never allow the undermining of this,” Nehawu’s statement read.

“The current wage agreements are sacrosanct and not open for review,” added the union, which represents workers in sectors including education and health.

The government agreed a three-year public sector wage deal in 2018 that runs until the end of March 2021. Nehawu says it hasn’t yet received a mandate from its members about how to negotiate over salaries from April 2021.

Fitch said on Friday that it did not expect Finance Minister Tito Mboweni to make clear commitments on reducing the public sector wage bill in a budget speech later this month.