Saudi Arabia is rejecting its rotating seat on the UN security council and says the 15-member body is incapable of resolving world conflicts.

The move came just hours after the kingdom was elected as one of the council's 10 non-permanent members.

In a statement made on Friday by the official Saudi press agency, the Saudi foreign ministry says the council has failed in its duties toward Syria.

"The kingdom sees that the method and work mechanism and the double standards in the security council prevent it from properly shouldering its responsibilities towards world peace," the foreign ministry said in a statement carried by state news agency SPA.

It says this alleged failure enabled Syrian president Bashar Assad's regime to perpetrate the killings of its people, including with chemical weapons, without facing any deterrents or punishment.

The ministry also says the council has not been able to resolve the Palestinian-Israeli conflict over the past decades and has failed to transform the Middle East into a zone free of weapons of mass destruction.

It is the second time this month that Saudi Arabia has publicly expressed discontent over what it sees as the security council's failure to take action to stop a civil war in Syria that has killed more than 100,000 people.

Saudi Arabia, along with Chad and Nigeria, were elected by the UN general assembly on Thursday to serve a two-year term on the UN security council as human rights groups called for all three countries to improve their records.

The Saudi foreign ministry said it was unable to take its seat until reforms were introduced, but did not specify what reforms it wanted.

US-allied Saudi Arabia has been angry over what it says is the failure of the international community to help either Syrian rebels fighting to topple President Bashar al-Assad or Palestinians seeking an end to more than four decades of Israeli occupation.

The security council has been split on how to handle the civil war in Syria, with western powers pushing for stronger sanctions against Assad and Russia vetoing resolutions to that end. Saudi Arabia has backed the rebels in that conflict.

The Saudis, along with other Arab states, have also often criticised the US for blocking international action to end the Israeli occupation of Palestinian lands seized in the 1967 Middle East war.

Earlier this month, the Saudi foreign minister cancelled a speech at the UN general assembly in frustration over the international inaction on Syria and the Palestinian issue, a diplomatic source said.