Students and staff are being put at risk by a lack of detail about how further education will reopen, it has been claimed.
With just six weeks until the new term, Colleges Wales said FE is not being treated on a par with schools.
The organisation said it remains unclear what practical arrangements and funding for September will be.
The Welsh Government said it recognised the challenges faced by the sector and is exploring ways to help with funding.
There are concerns relaxing social distancing rules will "will not be appropriate" for FE colleges, who offer academic courses and apprenticeships.
It is expected there will be more people on campus as new students and those returning to complete courses arrive.
Colleges Wales, which represents colleges in Wales, said extra funding will be required for a number of things, including helping students with learning difficulties.
All state schools will reopen to all pupils in September, if the virus remains under control - and pupils have had the chance to check in before the summer holidays
The Welsh Government has published guidance for schools to reopen, including staggered starts and breaks, increased hand washing, and a "period of flexibility" so teachers can focus on students due to sit exams and those just starting school.
'We need clarity'
But chief executive Iestyn Davies told BBC Radio Wales Breakfast, that with just six weeks until the start of term FE colleges were "no clearer" on how to reopen safely.
"Learners are at risk. There are lots of staff who don't know exactly what will be demanded of them," he said.
With FE colleges offering vocational courses, for people to specialise in subjects including engineering, Mr Davies said further education needed its own guidance, as they were "not the same as primary schools".
"Schools have had that guidance and their funding is set so we need that clarity on how we're going to go about it," he said.
He added: "We'll end up in a position where we're working and planning in the dark."
A Welsh Government spokesman said: "We recognise the importance of the further education sector in Wales and the challenges it is facing.
"We are actively exploring the scope to provide additional funding."