PF party has won a majority in parliament, according to partial results released Wednesday.
The figures from the Zimbabwe Electoral Commission showed ZANU-PF with 109 seats in the 210-seat parliament.The main opposition Movement for Democratic Change (MDC) had 41 seats.
The remaining winners were still to be declared.
European Union observers said the elections were held on an "unlevel playing field," citing voter intimidation, and mistrust in the electoral commission and media bias.
The assessment by the EU, which also questioned delays in releasing the presidential results, is considered important in determining whether Zimbabwe can improve its global reputation, which could help spark an economic resurgence.
If ZANU-PF wins at least 30 of the outstanding seats it would have a two-thirds majority that would allow it to make constitutional changes without the votes of other members of parliament.
Ballots are still being counted in the presidential election with results expected to be announced later this week.
The main candidates in that race are ZANU-PF's candidate, President Emmerson Mnangagwa, who took over after longtime leader Robert Mugabe's resignation in November, and opposition leader Nelson Chamisa of MDC.
Source: Voice of America