The Conservatives are planning to table amendments to the government’s Work and Families Bill when the legislation is put before MPs later this month.
The Tories fear that employers will be discouraged from hiring women of child-bearing age because of the plans to increase maternity leave.
The Work and Families Bill would allow women to take nine months’ paid maternity leave from April 2007. Some of that leave could also be transferred to their partners if the woman returned to work.
Eleanor Laing, the shadow minister for women and equality, said that although the party was not opposed to longer leave, it was important that any legislation wasn’t overly burdensome on business.
However, a spokeswoman for the Conservatives was unable to confirm what form the amendments were likely to take.
The CBI withdrew its support for the Bill before Christmas after chancellor Gordon Brown scrapped plans to allow firms to pass the handling of maternity pay over to HM Revenue and Customs.
CBI director-general Sir Digby Jones said that because employers would no longer be compensated through additional support, the CBI could “no longer support proposals to extend family-friendly legislation”.
The chancellor ditched the HM Revenue & Customs proposal in his pre-Budget report last November, saying the costs were “disproportionate” to the benefits to business.