by Newport Mind has called on people who work with EU nationals to refer them to schemes funded to help.
The deadline for applications is 30 June 2021, six months after the end of the Brexit transition period.
The Home Office said £17m had been spent on support and it encouraged anyone eligible to apply.
More than 74,000 people in Wales applied for the scheme by the end of November, although applications fell to about 2,000 per month between April and August amid the first wave of the coronavirus pandemic.
Tim Fox, a Newport Mind project worker in Wrexham, said: “It’s quite difficult to say in terms of exactly who is left, but there are quite a lot of vulnerable groups who we expect probably still need to make applications.”
Mr Fox said the pandemic made it “significantly harder” to get support for some people and has delayed the completion of applications.
Baby’s application delayed by Covid
Tiago Petinga, 32, who is originally from Portugal but has lived in Wrexham for 16 years, has successfully applied for settled status for himself, his partner and his eldest daughter.
But his youngest daughter, one-year-old Mirasol, is yet to apply because they have not been able to retrieve her documents from the Portuguese consulate during the pandemic.
“She was just born last January, and a few months after that all this started with Covid,” he said.
“We have to go to Manchester to get her documents and you can’t go from Wales to [England] as if it were a normal thing.”
Other vulnerable groups who may need help to apply include disabled people, elderly people, people who have left care and the homeless, Mr Fox said.
