Karen Bradley, the culture secretary, has said the government is considering changing the legal status of Google, Facebook and other internet companies amid growing concerns about copyright infringement and the spread of extremist material online.

The internet groups are considered conduits of information rather than publishers under UK law, meaning they have limited responsibility for what appears on their sites.

However, the chairman of the media regulator Ofcom said on Tuesday she believed the likes of Google and Facebook were publishers, raising the prospect that they could eventually face more regulation.

Bradley said she was wary of labelling internet companies publishers but that the government wanted to find a balance between harnessing the benefits of the web while making it safe for users and protecting intellectual property.

“We need to get the balance right so that we have a free vibrant internet that we can harness all the benefits from while protecting the intellectual property that is ultimately the thing that differentiates the United Kingdom from other parts of the world,” she said.

“I am looking into this. I am not sure the publisher definition in UK law would necessarily work in the way that people would like it to work. I think it would end up being very restrictive and make the internet not work in the way we want it to work.

“We need to be careful here that what we do is not a sledgehammer to crack a nut – a piece of legislation where we say under UK common law these platforms are now publishers, which could impact on freedom of speech, civil liberties and the ability of people to enjoy the benefits that the internet brings. But we have to do this in a way that doesn’t allow harm.”

Bradley made her comments as she was speaking to MPs on the digital, culture, media and sport committee. She also said the government could introduce new laws to regulate internet businesses.

Bradley said she wanted the UK to be the “safest place to be online” but that she was “clearly not” happy with the status quo and internet companies need to do more.

The government has this week proposed that internet businesses pay for measures to combat and raise awareness about online bullying and other web dangers. The voluntary levy on leading web players was part of a new internet safety strategy, which also includes proposals for a code of practice for social media companies.

However, Bradley said she was ruling nothing out in going further. “I would like to do as little legislatively as possible because I think legislation is a blunt instrument that often doesn’t deliver what you want it to deliver. But I don’t rule out bringing in new laws if that is what is required,” she said.

The culture secretary praised internet companies for being “proactive” on eradicating indecent images of children online and said she sensed a willingness among businesses to do more.

Bradley also answered questions from MPs about the BBC, Channel 4 and 21st Century Fox’s proposed takeover of Sky.

Last month Bradley announced she was referring the Fox and Sky deal to the Competition and Markets Authority (CMA) for a six-month investigation on the grounds of media plurality and broadcasting standards. Fox is controlled by Rupert Murdoch and his sons Lachlan and James.

Bradley said she referred the deal because a report by Ofcom created “sufficient uncertainty” about the tie-up. She pledged she would make the final decision on the deal following the CMA investigation on the basis of evidence, saying: “It is not based on personal emotion or feelings or views about the people involved.”