There is still a "serious imbalance" in female representation at leadership level in Irish firms, according to Balance for Better Business.
The latest report from the Government-backed body found that women made up 19.1% of publically listed boards in Ireland, compared to 16.4% six months ago.
Among companies on the ISEQ 20, female representation was above 25% - meeting the target set out for the end of 2020.
However other listed firms, as well as privately-owned companies, were not seeing the same level of improvement.
"Unfortunately there is a number of companies that are doing very, very little indeed," said Brid Horan, co-chair of Balance for Better Business.
"But we are heartened by the progress that has been made since our initiative was announced early last year. We'd be urging [ISEQ 20 companies] to continue progressing and for that progress to spread among all of them," she added.
However a handful of firms have made no progress at all - with 13 Irish-listed firms still having all-male boards.
Balance for Better Business had set a target of eliminating all-male boards at listed companies by the end of this year; a target that is almost certainly going to be missed.
"We do know that some of the companies are looking at appointments and we would really urge them all to take this very first step," Ms Horan said.
"Some of them are keeping their heads firmly down and not trying to engage - others are saying things which sound somewhat reasonable; like their terms of office of directors are not up."
Ms Horan said that others claim to be struggling to find suitable candidates for their board - however she says this is a less credible defence.
"Honestly there is a really strong pool of talented women available - experienced women and companies can benefit," she said.
"Those companies really need to step up - the chairs and directors need to own this issue, look broader than they're looking at the moment because the women are there, and make that first step," she urged.
Balance for Better Business has a range of targets through to 2023 - and is now broadening its work to include leadership positions and private companies.
Ms Horan said those targets will be a stretch but are achievable, and she believes firms will face increasing pressure to achieve them from a number of interested parties.
"It's proven by investor interest now that company performance improves with gender balance leadership - not just in boards but in executive leadership," she said.
"Big investment companies like Aviva, L&G, State Street and Blackrock are all taking a strong interest in this. Voting advisory firms are calling on companies to actually step up and do this.
"They're not doing that because they're big believers in equality - they're doing it because they believe it will improve the performance of the companies they're investing in," she stated.