CAFOD has said the resettlement of Syrian refugees into Britain must happen "as urgently as possible".
The Catholic charity also said Britain must start taking refugees that have already reached Europe, and not just those that are in camps in Middle Eastern countries neighbouring Syria like Lebanon and Jordan.
It was speaking after David Cameron met Syrian refugees in a camp in the Beckaa Valley in Lebanon, to see the people Britain would be helping first hand.
Meanwhile, Germany has closed its borders with Austria and suspended trains between the two countries, because it's struggling to cope with the number of refugees arriving. German politicians have said the country is expecting one million refugees this year - 200,000 more than previously thought.
And the British Home Secretary Theresa May has been in talks with European leaders regarding the crisis.
Neil Thorns, from the Christian charity, told Premier's News Hour: "They [the British government] will take 20,000 refugees under the Vulnerable Persons Scheme which is positive, but actually they've said it over the period of the five years of parliament, and actually we think that needs to happen as urgently as possible.
"They have to do something about the number of people in Europe as well, because those numbers are going to keep growing. There's over two to three thousand people entering Lesbos, the island in Greece, a day - and those figures aren't going to go down.
"They need to address the immediate situation about the refugees, but they also must not take their eye off the ball about dealing with the Syria conflict itself, and we must seek a peaceful diplomatic solution to that conflict because that's the key to everything."
Listen to Premier's Des Busteed speaking to Neil Thorns on the News Hour here: