A German comedian took matters into his own hands when Twitter failed to remove offensive hate posts on its platform.

Shahak Shapira painted 30 anti-Semitic, homophobic, Islamophobic, and racist tweets outside the company's German headquarters in Hamburg.

The Berlin-based performer, who is Jewish, reported around 300 tweets to the company but the majority were not removed.

I reported about 300 hate tweets. Twitter didn't delete 'em, so I sprayed them in front of their office #HEYTWITTER https://t.co/wPqiwaxd7J — Shahak Shapira (@ShahakShapira) August 7, 2017

Explaining why he launched his campaign in a YouTube video, Shapira said of the 300 tweets reported he received only nine responses from the company, each rejecting the suggestion that the tweets were a violation of the company's terms of service.

"I haven't received a single (message) telling me a tweet was actually removed," Shapira said, adding: "Occasionally, Twitter would remove a tweet without letting me know".

#HeyTwitter - A well thought out and targeted protest https://t.co/iqIcLI8Jy7 — Darrell Hawkes (@dazzywoo) August 9, 2017

The comedian decided to act by producing stencils of the most offensive tweets and spray painting them outside Twitter's offices so that its employees would have to see the posts as they entered the building.

#HEYTWITTER, this is inspired. You need to start paying attention. This is your platform. https://t.co/hi14IUIhUb — Astrid Bin (@disastrid) August 9, 2017

"Muslim scum", reads one tweet, "Jewish pig", reads another, while one uses a commonly used racial slur and describes black people as "a plague".

One passer-by said he worked in an advice centre for Roma people so was accustomed to "racist bull****" but was still taken aback by the tweets.

"It angers me that most people don't revolt against," the unnamed man says.

#HeyTwitter your downfall will be your failure to remove hateful reported content from your platform @twitter https://t.co/H7zr01JczT — Jennifer Jackson (@JJackson_RN) August 9, 2017

The campaign branded the hashtag #HeyTwitter, hopes to force Twitter into dealing with hate speech faster, and has picked up supporters the world over.

Well done! #HEYTWITTER @Twitter When we report, we hope it means you'll take action. It shouldn't take a million of us to show you a wrong. — lorenna cleary (@bipolarlioness) August 9, 2017

In its terms of service, Twitter says it "prohibits the promotion of hate speech globally" on the basis of race, ethnicity, sexual orientation, religious affiliation, and gender identity, among other factors.

In November 2016, Twitter suspended the accounts of several leading figures on the alt-right, including one of its key personalities, Richard Spencer.

His account, however, has since been restored.