Explicit references to women's sexual and reproductive health and rights must appear in any new set of development targets, and the UN panel producing a first draft must be bold and seek real change, a conference of parliamentarians heard on Thursday.

Baroness Glenys Kinnock, honorary co-president of the Labour Campaign for International Development and a former MEP, told the European Parliamentary Forum on Population and Development that women should be listened to, so that their needs – rather than what NGOs and governments think they need – are met. She criticised moves by conservatives, such as some members of the G77 group of developing countries and the Holy See, for trying to block progress for women.

Kinnock criticised the lack of reference to women's sexual and reproductive rights in the millennium development goals (MDGs) when they were launched in 2000. It wasn't until 2007 that references to family planning were included in MDG five.

"We have to ask how it can be that women are half the world's population but make up 70% of the world's poor," she told the forum, a network of MPs interested in protecting women's sexual and reproductive rights.

"We must ensure reproductive health and rights are a real priority at the G8 and G20, and work to close the gap in unmet need and extend universal access to services," she said, adding that the UN high-level panel, which is outlining a framework for development for after the MDGs expire in 2015, must deliver a bold document that includes references to women's health rights.

The panel is expected to publish its report this month, following meetings in London, Monrovia and Bali since October. A goal to promote gender equality and empower women is suggested in a leaked section of an early draft report, which includes promoting universal access to sexual and reproductive health and rights as a target. However, the draft is vague on detail.

Thursday's conference, held in London, heard of a growing backlash against women's rights that became acutely apparent at this year's Commission on the Status of Women (CSW), which advocated agreement on ending violence against women and girls. The commission faced strong lobbying by conservative governments and religious groups to remove references to reproductive rights, access to emergency contraception and sex education in its outcome document. After months of debate, and two weeks of intense negotiations in New York, an agreement was finally reached that did include these topics.

The battle at the CSW was a clear indication of the hostility that still exists towards women's rights, said Diego Palacios, a post-2015 co-ordinator at the UN Population Fund (UNFPA).

"Conservative groups are very active … with more resources. They can influence government, we are seeing that," he said. He said that although there is wide acceptance of the importance of women's sexual and reproductive rights, some of those involved in post-2015 discussions "still believe perhaps these [issues] could muddle the discussion" and don't want them included in explicit terms.

But Palacios remains optimistic. He said the success of the International Conference on Population and Development, held in Cairo in 1994 and reinforced in 1999, prompted "conservative forces" to push back on these issues at the UN when the MDGs were being debated. The Cairo agreement acknowledged that women's ability to control their own fertility should be central to development policy.

The MDG process was closed, added Palacios. "There were no women [involved] and no civil society organisations, even experts were left out. The concerns of women were not reflected," he said. The US was gearing up for an election and unwilling to rock the boat on such a divisive topic.

"Things are different now," he said. "In the post-2015 [discussions], we're hearing lots of voices on the importance of including the reproductive rights agenda … We have wide acceptance to consider the issue."

However, he urged MPs to continue to press their governments for action and remind them of the agreements and declarations on women's rights which they have signed up to. "You have a role that is critical," he said. "How many commitments has your government signed on women's rights, and sex and reproductive rights and health? It would be a shame to come to post-2015 discussions and forget about those discussions. We need to press governments.

"We need to ensure the post-2015 agenda brings right and centre the issues … otherwise it will be another missed opportunity and millions of women will suffer."