Forty of the 46 airplanes grounded this week in South Africa have been returned to service, the head of the country's aviation regulator said on Thursday.

The aircrafts had been stopped from operation over faults found in the maintenance unit of state-owned South African Airways (SAA).

South African Civil Aviation Authority (SACAA) Chief Executive Poppy Khoza told a news conference the regulator had made five findings during an audit at SAA Technical, after which it issued a prohibition order stopping some aircraft from flying.

As of Wednesday evening more than 80% of SAA's affected aircraft were back in service, SAA spokesman Tlali Tlali told Reuters.

The audit made two serious findings: that inadequately qualified personnel had signed off on maintenance work and that maintenance checks on flight data recorders and cockpit voice recorders had not been done correctly, Khoza said.

Other findings included SAA Technical's failure to implement previous findings and lapses in its quality management system.

A lack of clarity earlier in the week over the faults at SAA Technical had led to speculation that authorities were covering up major infringements.

Tlali said it was too early to quantify the financial impact from the grounding of its planes, dismissing an allegation that the faults were linked to SAA's perilous financial position.

"None of the audit findings made at SAA Technical can reasonably be associated with the state of finances we are experiencing at the moment," Tlali said. "No case has been made to support this claim because none exists."