Rachel Maclean, who is the minister responsible for safeguarding women, said the alleged behaviour was “shocking and unacceptable”, adding that there should be no place for it in the party or in Parliament.
Government chief whip Chris Heaton-Harris has launched an investigation after the allegations about the unnamed MP surfaced during a meeting of Tory MPs at Westminster on Tuesday.
Ms Maclean, who was at the gathering, said that everyone present had been “shocked and horrified” at what they were hearing.
It is completely and utterly shocking and unacceptable. There is no place for this in our party
“It’s just gruesome,” she told Sky News’s The Take With Sophy Ridge.
“I’m the minister responsible for safeguarding women and for creating laws which protect women against sexual harassment and violence against women and girls so it is deeply sickening and disgusting to hear that a male MP is watching porn.
“Action needs to be taken and I very much hope … we will see him out of Parliament, out of the party. I hope that’s where we get to.
“Of course, we have to hear the full facts of the case, we’ve only heard one side of the story, but that is already starting to happen.
“It is completely and utterly shocking and unacceptable. There is no place for this in our party.”
Ms Maclean added that she did not know the identity of the MP at the centre of the allegations.
Tuesday’s meeting was reportedly attended by between 40 and 50 Tory MPs, including Mr Heaton-Harris, Tory party chairman Oliver Dowden and Commons Leader Mark Spencer.
The meeting came amid reports 56 MPs, including three Cabinet ministers, are facing allegations of sexual misconduct referred to the Independent Complaints and Grievances Scheme.
It also follows outrage over The Mail On Sunday publishing “sexist” and disputed claims from unnamed Tory MPs that deputy Labour leader Angela Rayner tried to distract Boris Johnson with her legs during Prime Minister’s Questions.
Mr Johnson told the Commons “sexual harassment is intolerable” and “of course it is grounds for dismissal” when asked about the 56 MPs.
His aides insisted the Tory party does not have a problem with misogyny and sexism.
The Prime Minister’s press secretary said: “You will have heard the PM address this explicitly in Parliament today and over the last few days, saying there is absolutely no place for such behaviour and this cannot be tolerated in any workplace.”
A Conservative whips’ office spokeswoman said: “The chief whip is looking into this matter.
“This behaviour is wholly unacceptable and action will be taken.”