Under proposals to be voted on next month, women leaving work to having a child would be entitled to 20 weeks' leave on full pay.
The European Commission had originally proposed to extend maternity leave to 18 weeks, but has reduced this due to business concerns.
Under the current rules women in the UK are currently entitled to a year off
Under the current rules women in the UK are currently entitled to a year off, with the first six weeks on 90% pay, followed by 33 weeks on Statutory Maternity Pay of approximately £124 a week. The remainder is unpaid.
However, the British Chambers of Commerce (BCC) argues that this will still be a burden to British businesses, especially in this still challenging economic environment.
"This directive should be about setting minimum EU standards for the health and safety of pregnant workers - not adding new payroll costs for overburdened companies and national social security systems," said Kieran O'Keeffe, head of European affairs at the BCC.
"These figures confirm that the parliament's proposals are completely unaffordable as governments across the EU seek to deal with budget deficits and the aftermath of recession."