The House of Commons was forced to suspend sitting on Monday afternoon after water started pouring through the ceiling.
A message on the House of Commons annunciator read: “Today's sitting is delayed until 3.30pm. Due to a water leak in the chamber.”
The cause of the leak was not immediately clear, with MPs suggesting that it was caused by the building’s air conditioning system amid the hot weather.
Police officers could be seen entering the chamber with what appeared to be water-absorbent blankets to deal with the situation.
Labour MP Emma Hardy who briefly walked into the Commons chamber before being turned away told the PA news agency the water leak appears to be “just in front of the despatch box”.
The MP for Kingston upon Hull West and Hessle said: "I have just walked through and there are a lot of people working, around six or seven.
“Lots of blankets on the floor and a machine, which I'm not quite sure what is doing.
“It (the leak) is just in front of the despatch box, but the roof looks fine."
Ms Hardy said she has been told the issue should be resolved "as quickly as possible".
Meanwhile, the Commons’ Deputy Speaker, Nigel Evans, joked: “Somebody has just said to me this is one leak where we don't need an inquiry.”
“Start of Commons business will be delayed due to water leak from air conditioning unit - can’t cope with all the hot air in Parliament,” added Labour MP, Kevin Brennan.
Commons business had been scheduled to start at 2.30pm with prayers followed by work and pensions questions.
The Palace of Westminster is in urgent need of repair, with extensive works required to deal with asbestos, crumbling masonry and decades-old wiring.
A report earlier this year found that restoring Parliament in one scenario without MPs vacating could take up to 76 years and cost up to £22bn.
However, an alternative would be for MPs to decant while repair work is ongoing, which would take less time and would be likely to cost less money.