The two are likely to contest for the position of second deputy president when voting delegates gather to elect Cosatu's new leadership. The National Education, Health and Allied Workers Union (Nehawu), and the Police and Prisons Civil Rights Union are said to be questioning Ratshoshi's credibility.
NUM president Joseph Montisetse said there was no mutual agreement. "We are still lobbying each other. We will continue to lobby each other at the congress."
Union leaders also told Sowetan on Sunday that some affiliates are pushing for Nehawu first deputy president Mike Shingange to replace Tyotyo James as Cosatu's first deputy president.
James has served three terms.
There is also a view from the majority of Cosatu affiliates that Bheki Ntshalintshali and Solly Phetoe should retain their positions as general secretary and deputy general secretary respectively. Freda Oosthuysen is also set to retain her position as the treasurer.
Montisetse said it was time for James to go home and rest.
James declined to comment, saying: "Let's leave that to the congress."
The Liberated Metalworkers Union of SA spokesperson Dloze Matooane said the union believed in Losi's leadership.
Sowetan has learnt that Dlamini was no longer keen to contest his position.