Prime Minister Malcolm Turnbull’s weekend reshuffle will introduce several new faces to the cabinet, including Victorian Nationals MP Darren Chester, according to reports.

There’s speculation Mr Chester will take over the transport ministry, which belongs to outgoing Deputy Prime Minister Warren Truss.

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Mr Truss and Trade Minister Andrew Robb’s retirements at the next election have sparked a major reshuffle expected to be announced on Saturday.

Incoming Nationals leader Barnaby Joyce will get his choice of portfolios amid speculation Environment Minister Greg Hunt or International Development Minister Steve Ciobo could be in line for trade.

Other possible winners from the reshuffle include assistant ministers Karen Andrews, Concetta Fierravanti-Wells, James McGrath, Dan Tehan, Alan Tudge and Angus Taylor.

The Nationals’ new deputy leader, Fiona Nash, will be promoted to cabinet, increasing the number of women to five.

The reshuffle follows the departure of Human Services Minister Stuart Robert, who resigned over a China trip with a Liberal party donor, and Cities Minister Jamie Briggs, who resigned over a Hong Kong bar scandal.

Special Minister of State Mal Brough has been suspended from his job pending a federal police investigation into the copying of former speaker Peter Slipper’s official diaries.