More than 50 MPs say they will back a parliamentary motion urging the BBC to screen a charity appeal for Gaza, BBC reports.
The BBC says broadcasting the Disasters Emergency Committee film would put its reputation for impartiality at risk.
Criticism over the corporation's decision has come from archbishops, government ministers, charity leaders and 11,000 viewers.
Broadcasters ITV, Channels 4 and Five are to show the appeal later. Sky is yet to make a decision.
The DEC, which represents more than a dozen aid agencies, is asking for money to buy food, medicine and blankets following the Israeli assault on Gaza.
Labour MP Richard Burden is putting forward the early day motion.
He said: "Last time I looked... it was 57 MPs from different parties, Labour, Conservative, Liberal Democrats and others.
"I think there's great concern about what the BBC has done here."
Culture Secretary Andy Burnham has said the BBC is right to make its own judgement over the appeal.
BBC director general Mark Thompson said the danger for the BBC "is that this could be interpreted as taking a political stance on an ongoing story".
A string of politicians, including International Secretary Douglas Alexander, Communities Secretary Hazel Blears and opposition spokesmen, have urged the corporation to reconsider its position.
Their comments drew criticism from BBC Trust chairman Michael Lyons who said some were "coming close to constituting undue interference in the editorial independence of the BBC".
The corporation's former director general, Greg Dyke, said it was in a "no win" situation.
Liberal Democrat leader Nick Clegg has accused the BBC of getting its priorities "upside down".
The Church of England also waded into the row, with the Archbishop of York appealing for the BBC to consider humanity, not impartiality, and show the film.
In a direct appeal to the BBC, Dr John Sentamu said: "Come on Auntie Beeb. Wake up and get on with it."
The Charity Commission, which regulates UK charities, echoed calls for the BBC to reconsider, saying the work of the agencies would be hampered without "maximum public support".
However, Conservative MP Mark Field believes the row has boosted the profile of the appeal.
"The high profile controversy has given this appeal more publicity than it could possibly have imagined getting," he said.
"In many ways, it has achieved a lot of its aims that way without necessarily having to have a fully-fledged BBC coverage."