Parliament spokesperson Moloto Mothapo said yesterday morning that an announcement was likely to be today.
The motion is expected to be heard and voted on in the National Assembly tomorrow.
In June, the Constitutional Court ruled that Mbete, as Speaker, has the constitutional power to decide whether or not to hold a secret ballot during the motion.
Mbete previously said she would make her decision known before the August 8 vote.
Opposition parties have urged ANC members of Parliament to join in their motion of no confidence against Zuma.
Mbete told the Sunday Times this week that she was going to make the decision today, and that she was under immense pressure over her “difficult” decision. She also denied that she was employing delaying tactics.
Economic Freedom Fighters leader Julius Malema said last month that his party had already prepared legal papers to interdict Mbete should she refuse to allow a secret ballot.
“The papers are ready. When she gives that letter, we will not even read the whole thing, but just the conclusion. Once she says ‘open vote’, we are serving her.
“She has to give rational reasons. Failure to do that, and we will take her to court. We know she is unreasonable,” said Malema.
Zuma’s eighth motion of no confidence comes amid intensified calls from within the ANC for him to step down from leadership.
The ANC has said that any of its MPs who vote in support of the opposition’s motion of no confidence will face disciplinary action, with secretary general Gwede Mantashe earlier labelling it the “worst betrayal”.
ANC Chief Whip Jackson Mthembu said on Friday that voting in favour of the motion of no confidence in President Jacob Zuma would be like “throwing a nuclear bomb at the country”.
“The removal of the president will have disastrous consequences that can only have a negative impact on the people of South Africa,” he told reporters at Parliament.
Mthembu said it would result in the entire Cabinet having to resign, and a collapse in government. There would be deep and long-lasting ramifications, political instability, and economic uncertainty. — AFP