Suella Braverman has backed police over the handling of the coronation and insisted they had the right powers to crack down on Just Stop Oil protests.
The Metropolitan Police has been criticised over the arrests of six anti-monarchy protesters and three charity volunteers who were all later released without charge.
But the Home Secretary said the event was a “success for the police” and “people were able to enjoy that history event”.
“That’s thanks to the incredible hard work and initiative deployed by the police,” she told MPs.
But she said she wanted to see a swifter and more robust response to protesters such as Just Stop Oil.
She told the Home Affairs Select Committee: “I am incredibly frustrated when I see scenes of militant, activist, selfish protesters disrupt people from getting to work, getting to school, getting to hospital appointments, and we cannot see that.
“So I have to say, my view is quite mixed. I think that, yes, we want to see a more robust and swifter response from the police. And I think there is room for improvement, personally, going forward.”
But she added police had also done a “difficult job well”, highlighting the coronation as an example.
Mrs Braverman said Just Stop Oil protests had cost “millions of pounds” in policing costs.
She said a new statutory instrument – which was passed despite reservations about the process expressed by peers – would enable police to take quicker action against slow walking protests and “those bringing chaos to the law-abiding majority”.
Human rights group Liberty has taken the first step towards a High Court challenge over the legislation.
Liberty lawyer Katy Watts said: “The Home Secretary has sidelined Parliament to sneak in new legislation via the back door, despite not having the powers to do so.
“This has been done deliberately in a way which enables the Government to circumvent Parliament – who voted these same proposals down just a few months ago – and is a flagrant breach of the separation of powers that exist in our constitution.”
