Zimbabwe's former vice president Joice Mujuru has vowed to fight President Robert Mugabe's ruling Zanu PF party in her first press conference since she was ousted from government in 2015.

Once a powerful ally of Mugabe, Mujuru was sacked by the Zanu-PF party in 2014 after it accused her of plotting to oust and kill him.

"I'm neither a witch nor an assassin," Mujuru said, as she launched her new party, Zimbabwe People First (ZPF) on 1 March to challenge the president's 35-year rule.

Speaking to scores of people gathered in a local hotel in the capital, Harare, the former vice- president said: "I was once a part of Zanu PF, but our new party People First is completely a new entity with new values and followers. Our desire is to transform and build" [a new nation] because, she claimed, "Zimbabwe is a broken country" where people live under an unjust system that applies the law selectively.

Mujuru: ZPF's presidential candidate for 2018?

The 60-year-old was flanked by other former Zanu-PF heavyweights, former Presidential Affairs minister Didymus Mutasa and former Minister of Economic Development and Minister of Agriculture, Rugare Gumbo.

Mujuru, who is tipped to be ZPF's presidential candidate in the 2018 election, said it was time to build a new Zimbabwe in peace , adding that the nation needs reforms in all sectors.

Zanu-PF has nominated Mugabe, who turned 92 last month, for re-election in 2018, but in recent months, his wife, Grace, and Vice-President Emmerson Mnangagwa have engaged in a battle to succeed him within Zanu PF.

Mnangagwa was appointed to replace Mujuru after she was ousted.