UNITED NATIONS: The number of women in the top echelons of world politics has crawled to an all-time high, but progress is so slow that more quotas and incentives are called for, female leaders said at the United Nations on Tuesday.

Countries with legal targets and sanctions are making the biggest strides toward gender equality in politics, said the heads of UN Women and the Inter-Parliamentary Union (IPU), which released a yearly map charting women in global politics.

At the start of this year, one in five ministers around the world was a woman, the most ever and up 2.4 percentage points from a year earlier, the groups said.

The number of women in parliaments edged up less than a percentage point to 24 per cent in 2018.

"That's a lot of men making laws for all of us," said Phumzile Mlambo-Ngcuka, executive director of the United Nations' agency on women, at a news conference.

"We are obviously concerned. We were hoping that by this time we would have been very far in terms of the progress that we would have made," she said. "We do have snail's pace progress."

Of the 10 countries making the most progress in terms of female leadership, eight have some form of gender quotas in their laws or political parties, said Gabriela Cuevas Barron, president of the IPU, an international organization of parliaments.

"We need to make institutional changes to make faster cultural changes. Otherwise, culture takes too long, and we cannot afford to wait any longer," she said.

More than 130 countries have institutionalized some form of electoral gender equity rules, which might include quotas, legal targets, incentives for political parties that promote women and sanctions, according to the IPU.

But women advancing in politics often face harassment, legal discrimination, abuse on social media and violence, the advocates said.

"The environment right now is not the most enabling environment for women to rise," said Mlambo-Ngcuka.

"There is push-back," she said. "We just have to be stronger in pushing back against the push-back."

Nine countries, up from six in 2017, have 50 per cent or more women in ministerial positions, led by Spain, followed by Nicaragua, Sweden and Albania, the data said.

But women as elected heads of state dropped to 6.6 per cent from 7.2 per cent, and 11 countries have no female ministers at all.