Unemployment is expected to fall again today, although unions continue to highlight the number of people in jobs who want extra hours.
New jobless figures published by the Office for National Statistics are set to show the UK's headline employment rate has returned to its pre-recession level.
But the TUC said the number of people who wanted to work longer hours - so-called underemployment - remains almost a million higher than before the financial crisis.
In response, a Department for Work and Pensions spokesman said: "There are more people in jobs than ever before and the majority of the rise in employment over the last year has been in full-time positions, while more than four out of five people work part-time because they choose to do so.
“The truth is, our long-term economic plan is creating a better, more prosperous future for the whole country.”
Meanwhile, a new study showed that many jobs advertised online are "vague" and risk wasting people's time because they are unclear about hours, pay and other important issues.
Research by Citizens Advice found that nine out of 10 adverts on internet job portals failed to meet Advertising Standards Agency (ASA) requirements, The charity said adverts missing basic information about wages and hours left people unable to assess if a job would allow them to pay the bills or fit around commitments such as childcare.
Vague job ads also risked wasting employers’ time and money because a lack of information could increase the number of unsuitable applications and put stronger candidates off applying.