Three pairs of pants were hung in front of Sir Christopher Chope’s office front door in Christchurch, Dorset.
Their owner, Lorna Rees, is one of the veteran Tory MP’s constituents.
Upskirting is the practice of taking a picture up someone’s skirt without them knowing.
“No one should be able to photo my pants unless I want them to,” Ms Rees wrote on Twitter, along with a picture of her underwear.
Her “small protest” had been “flung together in anger and haste”, Ms Rees said, adding that “Friday was desperately frustrating”.
“I hope my anti-Chope constituency pant protest shows solidarity,” she wrote, referencing Gina Martin, who launched a campaign to make upskirting illegal.
The Voyeurism (Offences) Bill was stopped in its tracks when Sir Christopher objected to it being given a second reading in parliament.
The bill, which was proposed by Liberal Democrat MP Wera Hobhouse and supported by ministers, had been expected to get the nod through the Commons.
Theresa May said she was “disappointed the bill didn’t make progress”, adding that she wanted to “see these measures pass through Parliament – with government support – soon”.
“Upskirting is an invasion of privacy which leaves victims feeling degraded and distressed,” the Prime Minister said.
Former minister Sir Christopher was heckled with cries of “shame!” as he shouted an objection moments after the bill was called.
Fellow Tory MP Alec Shelbrooke described him as “a dinosaur, pure and simple”.
But after the parliamentary session, Gina Martin and her lawyer Ryan Whelan spoke to Sir Christopher, who agreed to meet them to discuss the bill.
“I’m positive and hopeful that he will become a supporter,” Ms Martin said.