He added that both women were now at the South African embassy in Tanzania's economic capital Dar-es-Salaam.
Quintal, the Africa program coordinator at the Committee to Protect Journalists, and Mumo, the organization's sub-Saharan Africa representative, were in Tanzania for a reporting mission.
"We are concerned for the safety of our colleagues Angela Quintal and Muthoki Mumo, who were detained while legally visiting Tanzania", Joel Simon, CPJ's executive director said.
The South African National Editors Forum (Sanef) has called on government to put pressure on its Tanzanian counterparts to get answers on why journalists Angela Quintal and Muthoki Mumo were detained in the country.
"The tweet by @angelaquintal was not sent by her", wrote Quintal's niece Genevieve Quintal, also a journalist. The officials searched the pair's belongings and would not return their passports when asked.
A South African news site, News24, reported that a tweet had been sent from Ms Quintal's account appearing to allay fears by confirming that she and Ms Mumo had been released but her family claimed that someone else may have been in possession of her phone.
While they are no longer in custody, Mabaya said Tanzanian authorities have their passports. "This shows someone is using her account". Quintal and Mumo's passports were confiscated and were yet to be returned.
Two Committee to Protect Journalists staffers have been released from detention in Tanzania and have left the country, the organization announced Thursday.
Since his election three years ago, Tanzania's President John Magufuli has cracked down on independent media, closing down critical newspapers, while rights groups have protested against the imposition of restrictive laws on freedom of expression.