Janusz Walus, who was imprisoned for the murder of anti-apartheid activist and SACP leader Chris Hani in 1993, is set to walk free after a Constitutional Court ruling on Monday.

Walus, a Polish immigrant, is serving a life sentence at the Kgosi Mampuru II Correctional Facility in Pretoria but will now be released "within 10 days".

He was convicted for Hani's assassination in October 1993. During the near-30 years he has spent in prison, he has made several attempts to be released on parole.

In February this year, the Daily Maverick reported that central to court proceedings at that time, Walus had effectively ticked all the boxes required to be given parole. This reportedly included "apologising to those affected".

During a hearing in February, it was argued on behalf of Walus that it was unconstitutional to keep him jailed without the option of parole.

Chief Justice of South Africa Raymond Zondo said on Monday that the March 2020 decision to reject Walus's request for parole has been reviewed and set aside.

He said Justice Minister Ronald Lamola and the correctional services commissioner will release Walus on parole within 10 days.

Right-wing politician Clive Derby-Lewis, who was alleged to have ordered the hit carried out by Walus, was granted medical parole in 2015. He died of cancer in 2016.

One of Lamola's reasons for previously denying the parole application was that the trial court that had jailed Walus wanted to send a message that assassinating political leaders was unacceptable.