Pembrokeshire's vital holiday let sector will be hit by an 85% average hike in business rates bills this spring, local AM Paul Davies has revealed.
Business rates bills are rising from April following a rates revaluation and the Welsh Assembly Government concedes that the self catering industry has been hit extra hard.
But it is refusing to give any special financial help to the sector.
Mr Davies says that Pembrokeshire will be hit the hardest as it has by far the greatest number of self catering holiday lets of any county in Wales.
"The figures show that Pembrokeshire has more than double the number of holiday lets than any other county in Wales so we will be particularly hard hit by this hike," he said.
"The average bill rise for self catering businesses across Wales is 55% but in Pembrokeshire this rises to 85%.
"We know that the overall number of visitors to Wales is dropping and we need to do everything we can to support the industry."
Local Government Minister Carl Sergeant told AMs in a letter last week that; "I am aware that valuations for the self catering sector as a whole have increased by significantly more than the average."
However he ruled out granting the industry any extra help because of financial constraints.
Mr Davies said the bill increases could lead to some operators closing down.
"I fear that these bills will either mean some businesses have to close or put their prices up which will make Wales a less attractive place to visit," he said.