Businesses will be able to use special software to easily find out how big any pay gap is between their male and female staff, the government has confirmed.
Ministers are hoping to encourage firms to identify any pay gap using the software, which is already being used successfully in Europe, and to take action.
Some firms, especially small ones, would find it hard to do this analysis, as their HR and payroll systems are separate, so the government hopes they "will no longer have any excuses not to look at their pay gap".
Jo Swinson, minister for women and equalities, told the Huffington Post UK: “More than forty years on from the Equal Pay Act, it is unacceptable that women still earn less than men.
“Most businesses do not intentionally discriminate against women on pay, but many are surprised by the result when they do the analysis.
“This software will encourage companies to look more closely at whether they pay their female employees correctly and make it much easier for them to report on it.
“We must continue to use all avenues possible to reduce the gender pay gap, and I look forward to seeing how this is put into practice by businesses. Companies are to blame for the gender pay gap, not women.”
According to the Office for National Statistics' Annual Survey of Hours and Earnings (ASHE) 2013, women earn just 80p for every pound men take home. In April 2013, men earned £12.86 per hour and women £10.33, a gap of 19.7%. This however has marked an increase on 2012, when the gap was 19.6%, with women paid £10.05 to men's £12.50.
Business groups have welcomed the government's offer of technology to help firms diagnose their gender pay gap, but urged ministers to go further.
Neil Carberry, employment and skills director at the Confederation of British Industry, said: "Smaller companies in particular may welcome this support but the pay gap has longer-term causes which need to be addressed.
"Too many areas of work – often those with high pay potential – are seen as male-dominated, with women steered away from options that would give them better access to higher pay and seniority. That’s why we need to provide better careers advice in schools to young women and boost support in the workplace for career development.”
Meanwhile, a spokesman for the Institute of Directors said: "That men and women should be paid the same wage for the same work goes without saying, and companies must strive diligently to make sure they pay both genders fairly.
"But simple software is likely to produce simple results. How will it account for different job titles, different company structures and experience? Smaller companies tend not to have rigid roles or fixed pay bands, how would the software deal with this? It seems unlikely that it will provide the accurate guidance the minister is hoping for."
However, Labour's shadow minister for women and equalities, Gloria De Piero, said: "The Government have tried the voluntary approach, and the evidence tells us that it just isn't enough to encourage employers to analyse their gender pay gap.
"Just 4 companies out of some 200 signed up to their scheme publish their pay gap. That's why Labour will call a vote in Parliament to implement pay transparency across all businesses with over 250 workers, so we can work with employers to tackle this.
"Women have waited long enough for equal pay and it's not good enough that the pay gap is back on the rise under this Government. A Labour Government will tackle this."
The coalition has already introduced the "Think, Act, Report" framework to improve gender equality and better equalize the level of pay between male and female staff, with 260 companies signed up like Tesco and Samsung.