A group of teenage girls and their mothers on a women's history tour were forced to call the police after being harassed by up to 20 boys on e-bikes.

Officers arrived at Marine Drive in Wollongong at about 2.20pm on Sunday after reports that 15 to 20 e-bike riders were refusing to leave the group alone. 

The group had been on the She Shapes History tour, which shares women's contributions to cities including Melbourne, Canberra, Sydney, Wollongong and New York. 

Officers patrolled the area but couldn't locate the e-bike riders. The next day, the incident was formally reported.

'It's by far the worst incident we've ever experienced on one of our tours,' She Shapes History's product lead Dr Zoe Condliffe said in a video shared to Instagram. 

'On Sunday, one of our tour guides was leading a tour - a small group of women, mainly mums and their teenage daughters.

'Before the tour could even begin, a group of around 20 teenage boys on bikes approached. They surrounded the group and started asking if they could join the tour. When the guide said no, they continued to push and heckle. 

'They didn't stop. When the women moved away, the boys followed. They mocked them. They harassed them.'

Dr Condliffe said the teenage girls on the tour were the 'least shocked of all'. 

'They felt like this was completely normal behaviour. It makes me feel sad that this type of behaviour is so expected,' she said.

'A group of women and girls gathering in their city to learn about their history should not feel like a radical thing to do. 

'Sadly, this is not at all an uncommon experience. Every day, women in cities all around the world are made to feel unsafe and like they don't belong.'

Tour guide Lindsay Burlton said the 15-minute ordeal felt targeted.

'There were two boys leading the bad behaviour and the rest followed in an alarming display of gang or herd mentality,' she told news.com.au. 

'I don't think most of those boys are inherently bad. I'd love to see society do more to educate and support boys on how to do the right thing in group peer settings.' 

The women decided to continue with the walk despite the incident. She Shapes History said it is 'more determined than ever to keep walking'. 

Australians were quick to share comments in support of the women. 

'This is vile, their parents should be shown this footage and their schools and/or employers contacted,' one person wrote. 

Another commenter tagged Prime Minister Anthony Albanese and NSW Premier Chris Minns with the message: 'This needs your attention.'

'It's not "boys will be boys", nor "it was just a joke". This is AGAIN a fundamental lack of respect and where misogyny germinates.'

A third added: 'These groups of boys on e-bikes are everywhere. They drive across roads blocking traffic and harassing pedestrians. 

'They are emboldened by the group dynamic and it's scary to think what could and probably will happen when these groups happen upon a lone woman or girl.'