The Labour Party has barred Saudi Arabia and Sudan from attending its party conference in Brighton.
In response, the League of Arab States wrote to Labour MPs and peers to tell them a reception and dinner hosted by Arab ambassadors would be cancelled.
“Unfortunately, the council of Arab Ambassadors has taken the decision to cancel its annual reception and buffet dinner,” the letter read.
It added: “Our council has decided to refrain from attending the Labour party conference this year due to rejection of both the Kingdom of Saudi Arabia and the Republic of Sudan’s application to attend the conference."
Jeremy Corbyn, the Labour leader, has called for the Government to stop selling arms to Saudi Arabia, arguing they are being used in Yemen's civil war.
"We are selling arms to Saudi Arabia… and at the same time we are sending aid in, we should not be doing both," he told the BBC's World at One programme.
Mr Corbyn went on to say it was important to ensure there is "a political process to bring about a ceasefire" in Yemen.
A Saudi-led coalition has waged a devastating air campaign in Yemen since 2015 to support the government in its war against Houthi rebels.
The fighting has killed more than 10,000 people and fomented a cholera epidemic, and the UN has called Yemen the world's greatest humanitarian disaster.
A spokesperson for the party told HuffPost: “Following evidence of war crimes committed by Saudi Arabia in its bombing campaign in Yemen and other large scale human rights abuses, the NEC agreed that the embassy’s application to attend the Labour Party conference would not be accepted.”
Labour's annual conference begins next Sunday.
