By Carien du Plessis

JOHANNESBURG (Reuters) -South Africa is mulling its options over an International Criminal Court (ICC) arrest warrant for Russian President Vladimir Putin should he accept an invitation to a BRICS summit in August, a South African government official said.

A member of the ICC, South Africa would theoretically be required to arrest Putin under the warrant issued in March by the court, which accused him of the war crime of forcibly deporting children from Russian-occupied territory in Ukraine.

Moscow denies the allegations. A senior Russian official also poured cold water on the idea of moving the summit to China.

South Africa had on Jan. 25 already invited Putin to the Aug. 22-24 meeting in Johannesburg of BRICS leaders of emerging economies, comprising Brazil, Russia, India, China and South Africa.

"There has been no firm decision," said Zane Dangor, director-general of the department of international relations, adding that ministers assigned to the matter would soon meet to consider a report setting out the options.

One option gaining traction among South African officials would be to ask the group's previous chair China to host the summit, a senior government official, who spoke on condition of anonymity, said on Wednesday.

Russian Deputy Foreign Minister Sergei Ryabkov said on Thursday that reports the BRICS summit would be relocated to China from South Africa were fake, Interfax reported.

The Kremlin had said on Tuesday that Russia would take part at the "proper level".

Former President Thabo Mbeki, whose views on international relations hold a lot of sway among government officials, said in a May 25 interview with radio station 702 that the summit was unlikely to take place in South Africa.

"Because of our legal obligations, we have to arrest President Putin, but we can't do that," Mbeki said.

A deputy minister, Obed Bapela, told Britain's BBC on Tuesday that South Africa was planning to pass legislation that would give Pretoria the option to decide whether or not to arrest leaders wanted by the ICC.

Bapela did not respond to requests for comment. However, a justice department official, speaking on condition of anonymity, said there wouldn't be enough time to get such a law approved by parliament before the summit.

South Africa on Monday issued diplomatic immunity to all leaders attending the meeting and a gathering of BRICS foreign ministers in Cape Town this week. The international relations department said this was standard procedure, however, for all international conferences in South Africa.

"These immunities do not override any warrant that may have been issued by any international tribunal against any attendee of the conference," department spokesperson Clayson Monyela said.

South Africa previously signalled its intention to withdraw from the ICC following protests about its failure to arrest Sudan's former president Omar al-Bashir, wanted on genocide charges, when he attended an African Union summit in Johannesburg in 2015.

The governing African National Congress decided in December that South Africa should abandon the process and try to effect changes to the ICC from within.

(Reporting by Carien du Plessis; Editing by Olivia Kumwenda-Mtambo, Edmund Blair and Sharon Singleton)