The South African Social Security Agency (Sassa) has filed papers at the Constitutional Court asking for a six month extension of its contract with Cash Paymasters Services (CPS).

Sassa spokesperson Paseka Letsatsi told News24 on Thursday that this was part of its "phase in, phase out" system to allow CPS to hand over to the South African Post Office.

"We don't want to collapse the system. That is the only reason we are asking for this extension," he said.

The Constitutional Court in 2014 ruled that the contract Sassa signed with CPS in 2012 was illegal and invalid.

In April 2017, the court suspended the order of invalidity until March 31, 2018, to allow the social development department and Sassa time to find a new provider.