The work policy came into effect for youths on Monday and will apply to sole mothers and other beneficiaries from October.
Anti-poverty campaigner Sue Bradford, from the Auckland Action Against Poverty group, said she was pleased the report had been critical of the "women-hating" welfare reforms.
"We are going backwards very quickly, and I'm really glad that this United Nations group has picked that up and referred to it.
"I just wish the Government would pay some attention to the report and think about what they're really doing here with their welfare reforms, because the reforms clearly discriminate against disadvantaged women," she said.
"We see it as misogynist, women-hating legislation in some regards because of the way it's going to disproportionately impact on unemployed women who are bringing up families on their own, women with disabilities - the very groups that this report is talking about."
Ms Bradford said the report should come as a warning to the Government.
"This committee is going to get even more concerned if Paula Bennett keeps going down the same track."
Social Development Minister Paula Bennett said the Government was not cutting benefits.
"As I have said publicly on many occasions welfare reform will not punish people for their circumstances but rather give them access to resources that were previously unavailable through the old system, particularly sole parents who move from the DPB to the new Jobseeker Support."
In its draft report, the UN committee said it was concerned about the situation facing disadvantaged groups of women, including disabled women, minorities, rural women and migrants - all of whom were more vulnerable to multiple forms of discrimination in education, health, employment and social and political participation.
It noted disabled women were disproportionately represented among those who lacked qualifications, did not work or who had low incomes.
The report recommended the Government provide more information on the situation facing disadvantaged women in regards to access to education, employment and healthcare services.
Social welfare was just one of the areas covered in the wide-ranging report, which praised New Zealand's progress since the last assessment but also criticised its performance in a number of areas.
The committee made recommendations on issues facing women such as family violence, access to justice, cyber-bullying, forced marriage, abortion law, education, and trafficking and exploitation.
Women's Affairs Minister Jo Goodhew said she had received the draft report earlier this week and would consider its recommendations.
"The committee commended New Zealand for having the fundamentals in place for the continuing advancement of women, but also made recommendations for improvement in a number of areas.
"I will be discussing these recommendations with my ministerial colleagues."
New Zealand is a signatory to the UN's convention on ending discrimination against women, under which progress reports are produced every four years.
Ms Goodhew presented New Zealand's report to the convention in the United States last month.
