The Archbishop of York has joined other church leaders and criticised recent comments by Government minister Phil Woolas.
Dr John Sentamu said comments by Mr Woolas that many lawyers for asylum applicants undermined the system and did "more harm than good" were wrong.
He also attacked "unmerciful" immigration policies.
He said asylum applicants, particularly those from Zimbabwe, should be shown more mercy and compassion.
In an interview with the Guardian, Woolas argued that most asylum seekers were economic migrants and criticised lawyers for "playing the system" when it came to the asylum appeals process and sowing "false hope" in clients' minds.
In the same interview, Mr Woolas said immigration was good for the UK but called for a "mature debate" on immigration levels which addressed public concerns on the subject.
Three of Britain's leading Free Church denominations immediately called for justice and compassion for asylum seekers, saying that their concerns were 'quite the reverse'.
The religion and society think tank Ekklesia also said that Mr Woolas should investigate his own government's bias against asylum seekers rather than attack those who give claimants access to basic legal justice.
Now, the Archbishop of York, in a speech to the Royal Society, has added his voice. He said the minister's recent remarks have muddied the waters in the immigration debate.
"For any honourable member to suggest that someone who has made out reasonable grounds, and has succeeded in their appeal under the due process of law 'has no right to be in this country' is a worrying development," Dr Sentamu said.
"May I be forgiven for suggesting that the honourable member in question does not advance his stated desire to have 'a mature debate about immigration' by this carry on?"
Lawyers acting on behalf of asylum applicants should not be castigated for pursuing appeals, he said, given the large number of initial decisions refusing asylum which were subsequently overturned.
Claims that some lawyers were dragging out appeals to prolong the amount of time their clients could stay in the country, and thus undermining the legal process, were simply not borne out by the facts.
He said government policy on immigration and asylum should show more compassion adding: "It is the tough talking of the unmerciful who would come down hard on criminals, immigrants and troublemakers…in the belief that this is the way to win hearts and minds".
He said asylum applications from those seeking to escape Zimbabwe's "brutal" government must be handled much more quickly.
He said it was "appalling" that applicants were not allowed to work while their applications were processed.
"The quality of our mercy in this area as a society has shown to be lacking," he said.