The Central Statistics Office said last week that unemployment stands at 14.8pc. But Goodbody said the real figure was much worse if those willing to work full-time were included.
"The true state of the unemployment situation is significantly worse if one counts those that are 'underemployed' -- that is willing to work more hours than their current part-time position provides. Including those underemployed, the unemployment rate stood at over 20pc" in the second quarter of the year, chief economist Dermot O'Leary said yesterday.
Mr O'Leary said he now expected the number of people with a job to fall by 1.2pc this year, which is four times more than his previous forecast.
These forecasts are now in line with the so-called "adverse labour market scenarios" contained in last year's PCAR stress tests, which tried to measure how the banks might be damaged by a slowdown in economic growth.
Mr O'Leary also halved his growth forecasts for this year to 0.3pc from 0.7pc and predicted the economy would expand 1.3pc next year rather than 1.8pc.
"Weaker domestic demand is the main driver of the 2012 downgrade, while a combination of lower export growth and lower consumption contributes to the downgrade for 2013," he said.
Mr O'Leary predicted that the Government would also downgrade its forecasts when it published a detailed analysis of the economy next month as part of the budgetary process.
Private and public sector economists have been repeatedly forced to lower their forecasts since the economy collapsed in 2008 because they have failed to predict the collapse in consumer and company spending.