Solicitor Richard Grogan has said.
An employment law solicitor says NPHET needs to recommend employers be allowed ask their staff whether they're vaccinated.
Currently employees cannot be asked their vaccine status as it goes against GDPR legislation.
Cabinet Ministers have been meeting to sign off on an exemption to isolation for close contacts who are fully boosted and are asymptomatic.
While those aged under 40 won't now need to get a PCR test if they get a positive antigen and will have to isolate for seven days.
Health Minister Stephen Donnelly says people in this age group will be asked to log their antigen tests through an online portal.
The new rules will come into place from midnight tomorrow.
However, Solicitor Richard Grogan says relaxing close contact rules for vaccinated people won't be effective in the workplace, if employers can't ask about vaccinations.
Richard spoke to Ciara Noble on Wednesday's Kildare Focus:

Clondalkin Attack Upgraded To Attempted Murder As Commissioner Says It’s Not Linked To Leixlip Case
Man Arrested After Overnight Burglary Spree And Criminal Damage In Naas
Homelessness Figures Hit New Record High Of 16,766 With Increases In Kildare
Family Of Shane O’Farrell - Killed In Hit-And-Run - Welcome Findings Of Bail Report
Milltown Father Shares Details Of Call With Junior Minister For Special Education
Irish Life Health Insurer Announces Price Increases
Animal Rights Assocation Condems Brutal Death Of Stag
Watch: Horse Charged At Gardai During Citywest Clashes Making Strong Recovery After Emergency Care