Investment property owners could be liable to heavy fines if they do not pay the new property tax on second homes by the end of September.
The €200 tax is payable to the local authority where the property is located.
Failure to comply with the new law could result in a fine of up to €2,000.
Analysts are advising second-home owners to find out which council they need to pay.
Karl Deeter, of Irish Mortgage Brokers, said failure to pay the tax on non-principal private residences on time will incur additional fines of €20.
“People may not be aware that this is coming up and if they do not pay it then there is a monthly 10pc surcharge imposed for failing to pay,” he said.
The late-payment fee will apply after October 31, according to Joe McCall, of Byrne & McCall. Unpaid taxes and fines will accumulate.
The new tax is expected to give local authorities up to €40m per year in additional funding.
Any outstanding charges and unpaid late payment fees will remain as a charge against the property for up to 12 years, even if the property is sold, according to Mr McCall.
Earlier this year, the Government decided to exempt mobile home owners from the tax. Newly constructed and unsold, never-let homes are also excluded from the tax.
People who atemporarily have two properties, for example, when they have just married or divorced or are in the process of selling and buying a home are also exempt, as are granny flats vacated by people now living in nursing homes.