The Vulcan Hotel is reprieved but has not been listed by heritage body Cadw
Buildings in Wales with a "social or cultural significance" should have new laws to help campaigners protect them, say Assembly Members.
The assembly's petitions committee cited the campaign to save Victorian-era Cardiff pub The Vulcan Hotel as an example of why new powers were needed.
A 5,000-name petition helped the Vulcan land a three-year demolition reprieve.
AMs said heritage body Cadw showed willing to protect it but could not do more without risk of legal challenges.
The Vulcan Hotel, which opened in 1853, is the only building left standing on Adam Street in Cardiff that has connections to the former Newtown area of the city.
Brewers SA Brain said in June last year that the pub would stay open "as long as it remains commercially viable".
'End of remit'
It had been due to close at the end of that month to make way for new developments.
In a last ditch attempt to retain it, campaigners had urged Cadw to list it but the application was turned down after it was decided that it did not qualify as a building of national importance.
Christine Chapman, chair of the assembly's petitions committee, said: "It is clear that Cadw showed willing in trying to protect the Vulcan, even asking the campaigners to find out more information and resubmit an application after the first attempt was turned down.
"But it is also clear that Cadw reached the end of its remit and simply couldn't do any more without running the risk of legal challenges on the grounds of the building not meeting specific criteria.
"The committee was told that there is some new heritage protection legislation which would tighten up laws in England and Wales but that that legislation, at the time, had not been allocated a slot for debate in Parliament.
"We therefore recommend the Welsh [Assembly] Government consider new guidelines or legislation to protect buildings which are important for social and cultural reasons."
The report said the committee also found that councils had no powers to stop the demolition or redevelopment of a building even if they had listed it as one which needed protecting due to its significance to the community.
The report also found that Cardiff council had previously lobbied both the Wales Office and the Welsh assembly for local authorities' powers to protect buildings to be strengthened.