LONDON, Aug. 2 (Xinhua) -- Britain has one of the highest gender pay gaps in Europe, the House of Commons Business, Energy and Industrial Strategy Committee said in a hard-hitting report on Thursday.

Rachel Reeves, the Member of Parliament who chairs the committee, said the study revealed that some companies have "obscene and entirely unacceptable" gender pay gaps of more than 40 percent.

The committee's report said it wants to introduce laws for smaller companies wherein they will have to report gender pay levels and publish action plans on what they are doing to close the gap. It also wants companies to explain why the gender pay gap is happening.

New analysis by the committee found that 1,377 employers -- 13 percent of the total -- have gender pay gaps in favor of men of over 30 percent.

Citing evidence that the pay gap is higher in smaller businesses, the report wants the government to force companies employing 50 or more staff to publish gender pay gap data. Currently, only companies with over 250 staff are required to supply the data.

Reeves said: "Gender pay reporting has helped to shine a light on how men dominate the highest paid sectors of the economy and the highest paid occupations within each sector."

Reeves believes that gender pay gap is not a problem only about fairness. "The gender pay gap must be closed, not only in the interests of fairness and promoting diversity at the highest levels of our business community, but also to improve the country's economic performance and end a monstrous injustice."

Reeves said a persistent gender pay gap shows that companies are failing to fully harness the talents of half the population.

She said the penalties of working part-time, both financial and in terms of career progression, are major cause of the gender pay gap.

"Companies need to take a lead. Why aren't they offering flexible working at senior levels? They must look at why they have a pay gap, and then determine the right initiatives, policies and practices to close it," added Reeves.

"The Prime Minister spoke about the gender pay gap as a 'burning injustice' and of closing the gap for good within a generation. It's now time for the government and businesses to deliver on that ambition," said Reeves.