Almost half of people don't know that calling their GP to discuss COVID-19 symptoms is free, a new survey has found.
Over a third (36%) of respondents, meanwhile, incorrectly think they could be charged for a test.
The ESRI is warning these "wrongly perceived costs" could deter or delay people from arranging a test.
The survey also found that more than 70% of people believe that someone who contracts COVID-19 has been reckless or careless in following public health advice.
The ESRI study, meanwhile, said that fear of being blamed may be a barrier to some people arranging a test quickly.
Dr Shane Timmons from the ESRI told Breakfast Briefing that some of the findings are worrying.
He said: "The aim of this survey was to try to identify anything that might be putting people off from engaging with the test and trace system as quickly as could be ideal.
"The good news is that everyone recognises this system is vital for maintaining control of the spread of the virus... but we did find a couple of issues."
Dr Timmons explained that most people know they can ring their own GP to arrange a test, but under a third were aware they could phone any GP or out-of-hours service.
He said people shouldn't lose sight of just how contagious the virus is.
He explained: "Even if you are being careful, there's no such thing as zero risk: bad luck can play a big role.
"The second reason that could put people off is if they're afraid they'll be judged negatively for having contracted the virus.
"It's important to know that if you do get a test result from the virus - be it positive or negative - it means you've done the responsible things. You've gone through the right steps."
