One in five vacancies remains unfilled because of a shortage of skilled workers, a report suggests.
A fifth of public sector organisations had vacancies compared with 14% of private firms.
There was a wide variation between professions, with the rate of unfilled jobs in hotels and restaurants was twice as high as in manufacturing.
The report, by Dr Andy Dickerson of Warwick University's Institute for Employment Research, found there was one vacancy for every two people looking for a job.
Ten years ago, there was just one opening for every 10 unemployed people.
In the last decade, unemployment has halved and job vacancies have more than doubled.
But high levels of job turnover made it difficult to predict where unfilled roles were more likely to be found, the report said.
Dr Dickerson found a skill "mismatch" between the unemployed and the vacancies available.
This, he added, left an important role for government-sponsored skills training and retraining initiatives.