The Rugby League Players' Association (RLPA) is asking the NRL for "further information and clear direction" ahead of a possible May 28 resumption.
The NRL has continued aiming to restart its season next month, although there were suggestions on Thursday it had encountered further problems.
Players are due to return to training on Monday, but reports said some stars were planning to boycott because no new pay deal had been finalised.
There is also ongoing uncertainty around the New Zealand Warriors, who are yet to be officially granted an exemption to enter Australia.
"We are in ongoing discussions with the NRL and our members today regarding a range of employment matters that require clarification," RLPA chief executive Clint Newton said in a statement on Thursday.
"We have requested further information and clear direction from the NRL and we are committed to continuing to work through this process in good faith."
While the RLPA is continuing to work towards a May 28 resumption, it is asking for clarity from the NRL around biosecurity and medical issues, wellbeing and insurance protocols, transparency around NRL revenues and distribution of player payments and detail on government approval regarding travel.