The Ministry of Defence is "tracking" 252 allegations of humanitarian law violations by the Saudi-led coalition in Yemen, the BBC has learned.
The UN estimates that up to 10,000 people have died in the country since war began in March 2015.
The MoD declined to say if British-supplied arms were involved in any of the allegations.
Former Business Secretary Vince Cable said he was "staggered" by the number of potential breaches.
Mr Cable told the BBC if he were still in government, arms exports to the Saudis would have been stopped "a long time before now".
Under UK rules, weapons may not be exported "if there is a clear risk that the items might be used in the commission of a serious violation of international law".
The British government told the BBC it kept the decision to export arms "under careful and continual review".
Next month, the Campaign Against Arms Trade will challenge the legality of the exports in the High Court.
Andrew Smith, from the campaign, said these new figures showed they should be stopped.
"It's such a significant number, such a high number, that it makes you wonder how high that has to get before the UK government practises more caution and stops selling bombs and fighter jets to Saudi Arabia," he said.
But former International Development Secretary Andrew Mitchell said the issue of weapons exports was a "red herring", as Saudi Arabia could obtain arms elsewhere and it allowed the UK to exercise "leverage" over the coalition's actions.
He called instead for an independent investigation into violations of human rights by both sides.
Stephen Twigg MP, who chairs the international development committee, echoed that call, saying: "The numbers of allegations are very, very significant."
In response, the MoD said: "The government is not opposing calls for an international independent investigation, but, first and foremost, we want to see the Saudi-led coalition investigate allegations of breaches of international humanitarian law which are attributed to them, and for their investigations to be thorough and conclusive."
It said the coalition's incident assessment team had carried out eight investigations on 4 August 2016 and a further five on 6 December 2016.
The BBC was not able to establish how many of the 252 allegations mentioned in response to a Freedom of Information request had been investigated by Saudi Arabia.
Critics argue that expecting the coalition to investigate incidents is effectively asking it "to mark its own homework."
In a statement, the Saudi government said "breaches of international human rights in Yemen were a serious issue" but "focus should be paid to the IHL breaches committed by the Houthis".
But it acknowledged "mistakes have clearly have been made with civilian losses", which have prompted a review of the coalition's targeting.
The Saudi government added its investigation of breaches of humanitarian law was comparable to the practice followed by the US and UK when they were faced with similar allegations in Iraq and Afghanistan.