Foreign Office Minister Kim Howells has condemned the violence in the Gaza Strip as "completely unacceptable".
Hamas seized Gaza after intense fighting
Mr Howells ruled out dialogue with Palestinian Islamist group Hamas, who seized control of the area last week and have been ousted from government.
He described Hamas as "extremist" and a "nasty bunch of religious bigots" who had carried out a "coup d'etat".
And he said the new emergency Palestinian government had Britain's full support.
Answering an urgent question in the House of Commons on Monday, Mr Howells said Britain would work with all those dedicated to a peaceful resolution of the conflict.
He was also asked to update MPs on efforts to release the kidnapped BBC journalist, Alan Johnston, abducted 98 days ago in Gaza.
Mr Howells said he hoped reports of an Hamas ultimatum to Johnston's kidnappers was not a case of them "using this as some kind of publicity stunt to try to win favour with the West".
The Hamas-led government was dismissed by Palestinian Authority President Mahmoud Abbas of Fatah, which was a junior partner in the unity government, on Sunday.
It came after some of the worst fighting that resulted in the Gaza Strip being seized by the Hamas armed forces in what the movement described as a "liberation".
Earlier on Monday, Prime Minister Tony Blair dismissed suggestions that refusing to give aid to Hamas was at odds with his general support for the idea of democracy. Mr Blair, appearing for the final time before the Liaison Select Committee before leaving office next week, said: "We have recognised Hamas as having won the election.
"Let's be absolutely clear what the problem is: the problem is not whether we recognise that Hamas has a mandate and have won the election.
"The problem is that if they want money from us - and we are putting hundreds of millions of pounds from the European Union into the Palestinian territories - we need to make sure that that money is not being used for them to buy weapons.
"They can get money from other people to go and do that, but they can't get it from us."
He said Britain and the EU "were perfectly happy to carry on giving the money to that government - provided that they eschewed terrorism and didn't end up in a situation where the money we gave them was going to be used for terrorism. What else could we do?"
Also on Monday the EU said it would resume direct economic aid to the Palestinian Authority to support the new Fatah-led government.
But EU foreign policy head Javier Solana said direct payments would not resume for the moment as the EU wanted to see proper financial mechanisms in place.