Council webcasting of meetings could become compulsory under Welsh Government proposals.
A grant of £1.25m was provided in 2013 to encourage authorities to install equipment in council chambers to allow them to broadcast meetings online.
But not all councils stream meetings and the latest Welsh Government move has been backed by all parties.
Conwy council said ministers will need to provide funding if the practice is to become mandatory.
Mark Drakeford, cabinet secretary for local government, said in a written answer to a question about the one-off funding in 2013 from Conservative AM Janet Finch-Saunders “18 out of 22 local authorities are broadcasting their council meetings to some extent”.
He has now proposed to make broadcasting of the meetings a “statutory requirement” as part of a package of proposals on local government reform, which ministers are consulting on.
Rhondda Cynon Taf ran an initial pilot of broadcasts, but chose to end the practice.
A spokesman for the authority said the council had utilised grant funding made available by Welsh Government, but did not extend its pilot “as the costs associated with installing the required technology were considered excessive at a time when the council faced significant financial challenges”.
“The council does tweet decisions made live from both cabinet and council meetings,” he added.
Conwy council has decided to investigate audio broadcasting rather than running video of meetings after its contract with an external provider came to an end. It has aired a limited number of meetings since last September.
A spokeswoman said the council had considered whether it could fund webcasting “given the high costs involved compared to the relatively low viewing figures” but said it felt the Welsh Government should provide funding if it is to become mandatory.
Figures for live broadcasts can be “minimal” but increase for archived videos, with viewer numbers ranging between 142 and 1,540, according to a paper seen at a council cabinet meeting.
The Welsh Local Government Association warned that longer-term IT and administrative costs for web-casting “will be considerable” and will need to be balanced against “prioritising front-line services”.
A spokesman said the WLGA had been “supportive of the roll-out of webcasting” but added the costs of a mandatory requirement “will need to be set out alongside any legislation”.
A Welsh Government spokesman said: “Progress has been made with the help of a single grant payment provided to local authorities but we now need to take this a step further.”
Ms Finch-Saunders, Conservative spokeswoman on local government, said she was concerned not all local authorities provide live streaming of council meetings.
UKIP spokesman, Gareth Bennett, said: “Local residents in Wales will be rightly wondering why some councils appear to have closed the door on local democracy”.
Sian Gwenllian, Plaid Cymru spokeswoman, said the broadcasting of public meetings “would enable more people to be engaged in local politics”.