The Green Party's Marama Davidson is expected to launch a campaign to be the party's next female co-leader.

Ms Davidson will be making an announcement at Ngā Kete Wānanga Marae in south Auckland on 4 February.

Green Party rules mean it's too early for Ms Davidson to officially announce a bid for co-leadership, which would explain why there's no hint at what the announcement could be. It's unlikely any other announcement from the MP would need to be kept under wraps in the same way.

When asked whether the event would be a co-leadership bid, Ms Davidson said she wouldn't be commenting as "the nature of the announcement is a surprise until the day."

Ms Davidson has previously not ruled out running for the position.

Ms Davidson has been in Parliament since 2015, when male co-leader Russel Norman's resignation saw her enter on the Green Party list. She's a vocal campaigner online, particularly when it comes to social issues.