In a declaration supported by 217 members of the Conservative dominated 290-seat parliament, the MPs condemned "the deteriorating situation and a great humanitarian tragedy" in Gaza.
"In recent days, the disastrous situation in Gaza has worsened and a great humanitarian tragedy is on the verge of taking place", the declaration said.
"In addition to savage killings, lack of water, electricity (and) health services have placed the population in the worst conditions," it said.
The deputies voiced "solidarity" with the Gazan people and asked the Organisation of Islamic Conference and Islamic parliaments to take a collective stance and respond to the "cries of Gazans."
Pressure has risen on Israel to unblock humanitarian supplies for the aid-dependent territory, after three days of bloody exchanges between Israelis and Gaza, controlled by the Hamas movement.
Four armed Palestinians were killed in a new outbreak of violence on Sunday despite a truce between Hamas and Israel in force since June 19.
Iran is a staunch supporter of Hamas, and does not recognise Israel's existence.
