CORK City Council is losing millions each year in unpaid and under-valued rates, with the situation unlikely to be corrected in the short-term.

A report compiled by City Hall's finance department shows some €19.4 million in rates arrears and a further €5.4 million that are deemed 'irrecoverable.'

Vacant buildings that derive no income but are still liable for rates is listed as one of the reasons for the large arrears.

While the city's collection rate increased to more than 76% in 2017, there are concerns about the length of time it takes the National Rates Valuation office to value new developments.

City councillors have reported that major new office and commercial developments often remain unvalued for as long as 18 months, reducing the city's income further.

In addition, the report states that there has been 'no progress' in including Cork city in a national revaluation programme.

"This would appear to indicate that it will be some considerable time before Cork City is the subject of a revaluation," the report notes.

While general trading conditions have improved, contributing to the rising collection figures, the report notes that there are still pressing issues in the city.

"Continued growth nationally is helping collection figures but many traders still find themselves in difficult trading conditions and some area in arrears since the downturn," the report states, adding that parking and potential flood defence works are a concern for many traders.

"The level of vacancy and of derelict or demolished property remains an issue. Progress has been made in recent times in relation to the redevelopment of some sites which will be of benefit to the city, a number of major sites remain undeveloped. Vacancy places a considerable rates burden on the owners of vacant property and this is a contributory factor to the overall arrears figure."

City councillors have raised concerns about the impact of the lost rates.

Fianna Fáil's Seán Martin urged the city to just write-off long-standing unpaid rates, claiming that some of these companies are no longer trading.

He said a more pressing concern is the delay in valuing new developments.

"We should be maximising our funding streams, not sitting on our hands," he said.

"It can take anything up to 18 months to value new developments and that is lost revenue to us. It is 2018; the idea that a local authority has to wait for Dublin to approve local valuations is crazy."

Sinn Féin's Thomas Gould said the situation is making a massive impact nationwide.

"It is public sector inefficiency in a nutshell," he said.

"We have lost about €2 million in the last few years by waiting for the rates department in Dublin to sign off on valuations. For us and other local authorities, that is huge money to be wasted."