The Equality Commission said a blanket ban placing restrictions on those applying to be Stormont special advisers would disproportionately discriminate against men, on 5 December 2012.
Eileen Lavery, the commission's head of strategic enforcement, was providing a briefing to the Finance Committee on a private member's bill being brought forward by the TUV's Jim Allister.
It aims to ban those convicted of an offence carrying a sentence of five years, or more, from holding the post of special adviser to a Stormont minister.
Ms Lavery said creating a complete ban "seems to not make sense to us".
"We do appreciate the importance and the sensitivity around these positions," she said.
"But we caution against the use of the blanket exemption where it cannot be objectively justified."
She added that those who had a serious criminal conviction were much more likely to be men.
"We feel very strongly that an applicant could complain that the criterion of prohibiting anyone who had a serious criminal conviction disproportionately excludes men," she said.
In response to a question from the DUP's David McIlveen, she said the commission was not suggesting vetting should be removed, but would recommend that if an applicant was found to have a conviction, the onus would be on the employer to consider its material relevance to the position.
Ms Lavery also said that an exemption existing in fair employment law that stated it did not protect anyone with conflict-related offences "no longer makes sense".
She said the Good Friday Agreement released conflict-related prisoners so they they would not "fester" but become "good citizens" and therefore any restrictions that would prevent this would "not rest easy".