Freedom of Information requests 'puts strain on councils'
Local authorities say they are struggling with the number of Freedom of Information (FoI) requests which have more than doubled since 2005.
The warning comes from the Welsh Local Government Association (WLGA) which says councils cannot afford to spend lots of money on "unnecessary" queries.
The number has risen from 3,530 in 2005 to 9,304 last year, according to figures obtained by BBC Wales.
Requests can be made to any publicly funded body in the UK.
They are frequently used by journalists, businesses and politicians to obtain information which is not already publicly available, although any member of the public can make a request.
Under the Freedom of Information Act, each request should not cost more than £600 for central government to answer and should be less than £450 for other public authorities.
A study by University College London estimated the average cost of an FoI request to be £293.
Based on that figure, public bodies could have spent as much as £4.5m answering requests last year.
Steve Thomas, chief executive of the WLGA, said with cuts in public expenditure councils could not afford to spend huge amounts of money on "unnecessary" FoIs.
"Every pound and every shilling is required at the moment to push into frontline services," he said.
"I'm afraid that FoIs, particularly in the way they're coming in and the weight they're coming in, are in some areas detracting from frontline services."
Merthyr council received the most requests per head of the population in Wales.
Officers say they used to get around 10 per month but the number has risen to around 60 in recent years.
They could have spent as much as £160,000 last year answering the queries - equivalent to the cost of around seven newly qualified teachers.
Those who have used the act say it's important for transparency.
Gary Willetts from Llandudno Junction wanted to find out more about a £1m overspend on a bridge rebuilding project.
Conwy council initially refused to disclose details he asked for about their spending in a FoI request, but they were forced to do so when he appealed to the information commissioner.
"Some people use it for a malicious purpose or, if they are in business ,they want to gain confidential information," said Mr Willetts.
"But in real terms it was a great boost because it now stops councils, hospitals and water authorities from hiding information from the council tax payer.
"I think the more and more open these public bodies are, the less use will be made of the Freedom of Information Act.
"These members of councils are trustees of the council tax payers money and as trustees they have an obligation to be open and honest with us.
"And if they're not, the Freedom of Information Act is an essential tool to use".
The Welsh government defended its approach to openness and information.
A spokesperson said: "As a government, we are fully transparent and open in the way we conduct our business on behalf of the people of Wales.
"We have a longstanding commitment to maximising openness and this is an area where the Welsh government has been delivering for years through the proactive publication of cabinet papers, ministerial decision reports and details of payments over £25,000."