Upskirting has now become a criminal offence in England and Wales punishable with a maximum two years in prison.
The law comes into force following an 18-month campaign led by 27-year-old Gina Martin to make the act a specific offence after two men took a picture up her skirt at a music festival in 2017.
Campaigners have long claimed the lack of a specific upskirting offence has deterred victims from coming forward and some police forces have been unsure how to investigate allegations.
Ms Martin, who worked with lawyer Ryan Whelan to lobby government, said: "During the 18 months of campaigning undertaken, I received hundreds of messages and stories from those who had been upskirted.
"The fact that reports are increasing shows that victims feel more empowered and emboldened to report what has happened to them than before the campaign, which is wonderful - this was just as important to Ryan Whelan and I as the law change.
"We hope that people continue to feel comfortable reporting upskirting under the new Voyeurism Act."
The Ministry of Justice said the new law introduced in England and Wales on Friday "bans the degrading practice to deter perpetrators, better protect victims, and bring more offenders to justice".
Previously, those targeted were forced to seek prosecution under existing harassment, voyeurism or indecency laws, but said loopholes meant it was often difficult to secure a conviction.