Mujuru was Mugabe’s deputy for a decade and seen as the veteran president’s likely successor until he fired her in 2014, accusing her of leading a plot to oust him.
In her first public address since then, she told reporters on Tuesday the new Zimbabwe People First party would bring jobs and review the ruling ZANU-PF party’s divisive black economic empowerment laws, which critics say have scared off investors.
She said she was open to alliances with other opposition groups before 2018 presidential elections.
There is no independent estimate on the size of her support. Other parties have previously said they would be open to talks with Mujuru.
“Today we confirm our existence as a viable, inclusive home-grown political party,” Mujuru, 60, said to cheers and ululation from supporters.
“We are not fighting one man but a system, that system which is unjust,” she told an audience including reporters, Western diplomats and four former cabinet ministers fired by Mugabe.
ZANU-PF national commissar and cabinet minister Savior Kasukuwere described Mujuru’s party as a “gathering of losers”.
“We will defeat them anytime. We are ready for them. What is it that they want to tell us that they couldn’t do for 34 years when they were with us in the (ZANU-PF) party?” said Kasukuwere.
Zimbabwe is struggling to emerge from a deep recession that shrank its economy by nearly half during the decade to 2008. It is also facing its worst drought in years