Nick Clegg was accused of a "patronising" attitude to critics of the Government's welfare reforms by a former Liberal Democrat minister, who said the system was leaving people "destitute".
The Deputy Prime Minister accused the Archbishop of Westminster, the Most Rev Vincent Nichols, of exaggerating the effects of the coalition's welfare reforms.
But Lib Dem MP Sarah Teather said Mr Clegg's intervention was not "very helpful" or "well informed" as she backed the Archbishop's stance.
The Roman Catholic Archbishop, who is set to be made a cardinal, said it was a "disgrace" that in such a wealthy country there were people who could not afford to feed themselves.
Mr Clegg responded by saying: " I think that to say that the safety net has been removed altogether is an exaggeration, it is not right."
But on BBC2's Newsnight Ms Teather said it was "r ather a patronising response from my leader" which was "not very helpful and not, in my view, very well informed either".
The Brent Central MP added: "If I think about the experience of a lot of my constituents I'm afraid I'm seeing far too many people who are made destitute and put into severe poverty by the benefit changes.
"For example I had a woman where the whole of the last trimester of her pregnancy she had no money whatsoever.
"I had another case where somebody was sanctioned for failing to turn up to an appointment when she was having surgery for cancer.
"So I'm afraid the Archbishop's criticism this week really chimes with my own experience."
She said Iain Duncan Smith's universal credit agenda of simplifying the system and making work pay had been "cut against" by budget cuts and "directly political interventions that are more about trying to demonstrate whose side we are on rather than really about helping individuals get back into work".
Tory MP Steve Baker praised the Work and Pensions Secretary as a "deeply moral man" but acknowledged there were problems with the welfare system.
He said: "The clergy are right to speak up for the poor, of course, but I don't think it was right when the Archbishop said that the welfare state had been torn away. I don't think that stands up to scrutiny.
"We are still paying jobseeker's allowance, we are still paying the pension, the health service is still there.
"But is it true the welfare state is failing people and leaving them destitute? Well I'm afraid it is and the bureaucracy is always inefficient and it's not a way of dispensing kindness. "
Tory MP Nadhim Zahawi defended the welfare changes on BBC Radio 4's Any Questions: "I can tell you, from my family's own experience of being on welfare, that one of the hardest things to do is to motivate yourself to wake up in the morning, have a shave, have a shower and actually go out and actually look for work.
"And actually we need a welfare system that supports people who want to go out and find a job and try and keep a job down.
"The job centres have a very clear instruction that sanctioning should not be a first resort, it should be a last resort. People are able to challenge a sanction.
"And of course the job centres under this Government have been allowed to signpost people to food banks. I think that's an important change to the system."
He added: "My position is to make sure that the job centre staff and people listening to this programme know that there is a contract between people going looking for work and the state, and that contract is a two-way contract.
"When you are in work if you decide not to turn up for work there are consequences attached to that. I think that is important to also remember, because we need to change that culture."