His comments come as more than 1.5m people have now fled Ukraine into neighbouring countries, according to the UN.
There have been reports of shelling in Ukrainian cities on Saturday night with a planned evacuation of Mariupol taking place after Russian President Vladimir Putin invaded Ukraine.
The Justice Secretary was asked on the BBC’s Sunday Morning programme about reports that 150 Ukrainian refugees had been turned away at Calais because they did not have a valid visa.
He said: “Look, if we just open the door not only will we not benefit the people that we need to, the genuine refugees, but I think we undermine the popular support for this very thing, so I don’t think that’s the right thing to do. We need to make sure that we’re acting for those that need our support.”
Mr Raab said he expected up to 200,000 Ukrainians could come to the UK through the family dependents route and that “the humanitarian route, that is uncapped”.
“We’ll work with the United Nations and other agencies, but also individuals, business, charitable sponsors here, and that route for Ukrainians fleeing persecution is uncapped. And of course, we provided £220 million of humanitarian support, which is directly for the Ukrainian people, but also for those countries taking refugees.”
He added: “Of course, you find this with conflict situations, most people want to go… either stay in their country of birth and origin or go to a country nearby, so they can return later. I think we can expect that with Ukraine.”