"Getting a replacement phone shipped but do wonder if it is bad luck or a more common issue with the phone."
Some users said they were able to resolve the issue by re-setting it or turning up the sensitivity.
However, most said they needed a new phone.
"They recommended I order a new phone (now on backorder) and send them back the defective device. They emailed the return shipping label to me," another user said.
At the end of last month the firm launched its highly-anticipated flagship "iPhone X killers", the Galaxy S9 and S9 plus.
Both feature a familiar all-screen design, but have a re-invented camera system that has been dubbed a "game-changer".
But issues with the touchscreen have dampened enthusiasm for the device.
"I have a dead spot at the top left of my phone (S9+). It works sometimes and then won't work," another user wrote on the company's official communities page.
"My S9 has dead spots as well, right out of the box," said another.
This latest disaster will do nothing to reassure customers after exploding batteries in the Note 7 tarnished the brand's reputation.
Read more: Samsung suspends production of Note 7
Within weeks of being launched last year, the phones were catching fire - and in some cases exploding.
By September the company stopped producing the phone and sent replacements. It lost around US$26 billion ($35b) in value in the stock market.
Samsung has been quick to respond to this most recent problem and issued a statement saying; "At Samsung, customer satisfaction is core to our business and we aim to deliver the best possible experience.
"We are looking into a limited number of reports of Galaxy S9/S9+ touchscreen responsiveness issues.
"We are working with affected customers and investigating," writes Engadget.
Customers who have been affected by the problem have been urged to get in touch with the company.
MailOnline has contacted Samsung for comment.