Sweden became the first European country in 2013 to grant automatic residency to Syrian refugees and has since seen asylum requests rise to record levels, which are still expected to reach about 90,000 in 2015.
Previously no more than 200 asylum seekers were permitted to stay in one centre. But under the new rules, the Migration Board can sign a basic contract for 350 places, including two supplementary agreements of 150 places each after the first ones have been filled.
According to the Swedish Migration Board's latest prognosis, 15,000 more asylum places will need to be created in the coming year.
Last week a survey by pollsters Ipsos commissioned by Swedish newspaper Dagens Nyheter suggested that more than 60 percent of Swedes believe that immigration is good for the country, but just ten percent agree that integration efforts are working well.
Morgan Johansson told local news network P4 Kristianstad that he had been "taken by surprise", but added that he had not been injured.
"But you shouldn't treat these things too lightly either. You can't just say 'move on', because of course it's serious," he said.
The attack on the politician took place as Sweden's Prime Minister Stefan Löfven reiterated his commitment to helping refugees, but called on other EU nations to share the burden.
"We need to provide security for the refugees who risk facing death just a few mile off the coast of Europe, and get more of the EU member states to take responsibility for refugee protection," he said in a speech at a school in Gothenburg.