South African President Cyril Ramaphosa (AFP)

Arresting Russian President Vladimir Putin would amount to a "declaration of war" on Russia, South African President Cyril Ramaphosa wrote in court papers released on Tuesday.

Putin has been invited to a BRICS summit in Johannesburg next month but is the target of an International Criminal Court arrest warrant -- a provision that Pretoria as an ICC member would be expected to implement.

South Africa is experiencing a diplomatic dilemma in court, where the leading opposition party, the Democratic Alliance (DA), is pressuring to ensure the Kremlin leader is held and handed over to the ICC if he steps foot in the country.

But in a responding affidavit, Ramaphosa described the DA's application as "irresponsible" and warned that the country's national security was at stake.

"Russia has made it clear that arresting its sitting President would be a declaration of war," he pointed out.

"It would be inconsistent with our Constitution to risk engaging in war with Russia," Ramaphosa indicated, adding that this would go against his duty to protect the country.

The arrest would also undermine a South African-led mission to end the war in Ukraine and "foreclose any peaceful solution", he wrote.

South Africa is seeking an exemption under ICC rules based on the fact that enacting the arrest could threaten the "security, peace, and order of the state," the President noted.

Last month, Ramaphosa led a seven-country African peace delegation including representatives from Egypt, Senegal, and Zambia to talks in Kiev and Saint Petersburg.

The ICC treaty states that a member country should consult the court when it identifies problems that may impede the execution of a request and that the court may not proceed with requesting an arrest if this would require a state to break international rules on diplomatic immunity.

South Africa is the current chair of the BRICS group, a gathering of heavyweights that also includes Brazil, Russia, India, and China, which sees itself as a counter-balance to Western economic domination.

Putin is sought by the ICC over accusations that Russia allegedly deported Ukrainian children.

South African Deputy President Paul Mashatile said in recent interviews with local media that the government has been trying to persuade Putin not to attend the summit physically -- but so far unsuccessfully.

Signed in June and initially marked as "confidential", Ramaphosa's affidavit was published on Tuesday, after the court ruled it be made public.

DA leader John Steenhuisen praised the court's decision, describing Ramaphosa's argument that South Africa risked war with Russia as "farcical" and "flimsy".

It is noteworthy that Pretoria has ties with Moscow dating back decades, to when the Kremlin supported the ruling African National Congress party in its struggle against apartheid.