The gender pay gap is still increasing, according to figures from the Office for National Statistics.
On the basis of average full-time hourly earnings, excluding overtime, the gender pay gap for full-time workers has increased from 17% in 2007 to 17.1% in 2008.
Gerwyn Davies, public policy adviser at the Chartered Institute of Personnel and Development (CIPD), said she was "disappointed" with the ONS figures.
"The figures demonstrate that even greater effort will need to be made by employers and the government to narrow the gap. But it is simplistic to conclude that the gender pay gap is the result of overt pay discrimination by employers," she said.
"The gap mainly reflects variations in the type of jobs done by men and women, different working patterns and, in particular, the impact of child and elder care on women's career choices and hours of work. All these factors need to be taken into account when devising changes to policy and practice designed to close the gap."
TUC general secretary Brendan Barber said: "The increase in the gender pay gap makes the case for decisive action more pressing than ever. This is an injustice for both women and men.
"As redundancies mount, more women may find themselves as the sole or main income earner. It's more important than ever that they are not underpaid for what they do."
In March this year, a poll of more than 1,000 people, commissioned by the Public and Commercial Services Union, found that 88% of respondents believed the government should be responsible for reducing the gender pay gap.