Almost 80,000 workers in Ireland are engaged in the black economy, earning an estimated €160m a year, according to the first major EU-wide survey on undeclared work published last week.

The survey by the Dublin-based Eurofound revealed that, at 4%, the level of undeclared work – which is kept hidden from the Revenue Commissioners – is below the EU average of 5%.

However, when it comes to the number of hours of undeclared work done in a year, Ireland climbs up the 'black economy' league table.

According to the survey, Irish workers are engaged in 253 hours of undeclared work in a year, with each 'undeclared worker' worker pulling in €2,013 tax-free per year.

This figure puts Ireland in the top half of the table of 27 EU countries surveyed and fifth worst of the 15 original EU countries.

Reacting to the report, a spokesman for Revenue Commissioners said it is pleased that Ireland is included "in the better end of the league table. We are, however, always very cautious about estimates of undeclared income," he said.

Bulgaria is by far the worst offender with each worker on 649 hours of undeclared work a year followed by the Italians who admitted to 550 hours of undeclared work a year.

Domestic cleaners, childminders, small builders involved in household improvements, and hairdressers are the most prevalent jobs in the black economy.

The revenue spokesman added that 32 officers are being assigned to the new Joint Investigations Units (Revenue, Social Welfare and Enterprise, Trade and Employment), which investigates the hidden economy.