Witwatersrand University staff vowed on Wednesday not to back down from its salary demands presented to management during a one-day strike this week.
The Academic Staff Association of Wits University (Asawu) which on Monday walked out of talks together with the National Health and Allied Workers Union (Nehawu), said the same demands would be presented again.
"Management's proposal is unacceptable... we have been requested to put our demands in writing by Friday and we shall do so again," said Asawu president David Dickinson.
The university said on Wednesday that it was waiting for a response from Asawu and Nehawu to provide a counter-offer or reasons for their rejection of management's proposals.
The third union, the Wits Administration, Library and Technical Staff Association (Altsa) signed on Monday night, hours before the planned one day strike by staff.
Nehawu spokeswoman Khomotso Makhupola said her union would not sign for anything less than what it demanded.
The unions demanded more funds for research projects as well as improved salaries.
They demanded a nine percent increase while management offered 6.8 percent for support staff and 7.55 percent for academics.
They had also complained about the lack of parking space and child care facilities.
Wits spokeswoman Shirona Patel said the institution was currently a "market leader" regarding academic remuneration.
"Wits has offered competitive salary packages which have consistently exceeded inflation," she said in a statement.
A salary analysis against those offered by four other top universities in the country showed that Wits was currently a market leader, she said.
Patel said she could not name the four universities because their salary scales were not in the public domain.