The number of pregnant women and new mothers losing their jobs has shown an "alarming" rise as employers target them for redundancy ahead of childless colleagues, according to an alliance of support groups launched this week.

The Alliance Against Pregnancy Discrimination in the Workplace has identified a sharp increase in women consulting lawyers or calling helplines because their jobs have been terminated during maternity leave or pregnancy.

"It appears that some employers are using the recession as an excuse to break the law on discrimination," the alliance warnedyesterday. Campaigners said that the "long-term consequences of job loss as a result of pregnancy or maternity leave jeopardise women's financial security for their whole lives".

About 30,000 women are estimated to lose their jobs as a result of pregnancy every year, according to the Equality and Human Rights Commission, but that figure is expected to rise because of the economic downturn. The government is not collecting data on this kind of discrimination, and it is too early for the tribunals service to have tracked a spike, but campaigners say a wealth of anecdotal evidence suggests there has been a steep increase. Camilla Palmer, a lawyer specialising in pregnancy and maternity-related discrimination with Leigh Day & Co, said that more people were losing their jobs across the board, but that pregnant women and new mothers appeared to be disproportionately affected.

Cases where women on pregnancy-related leave lost their jobs because whole departments closed were discounted, she said, but the firm was dealing with more calls from new mothers singled out for redundancy.

The increase in calls from women concerned about pregnancy-related unfair dismissal was so steep that the company launched a dedicated helpline last month to offer preliminary advice on employment rights in this area.

Elizabeth Gardiner, parliamentary policy officer at Working Families, a campaign group on work-life balance that is part of the alliance, said women had approached them with more severe examples of discrimination in recent months. "Employers seem much more willing to flout the law," she said.

Campaigners are concerned that attitudes towards maternity rights have hardened among many employers whose businesses are struggling in the economic downturn. The alliance believes that new mothers will be seen as "fair game" for dismissal during the recession, and cites remarks by Sir Alan Sugar as evidence of a new hostility in the business community to enhanced maternity rights. Sugar said: "We have maternity laws where people are entitled to have too much. Everything has gone too far."