United is in the market for a new striker this month and have held extensive talks to sign Weghorst, who is currently on loan at Besiktas from Burnley.
Erik ten Hag’s side has already seen its first offer rejected as it attempts to persuade Besiktas to cancel Weghorst’s season-long loan, metro.co.uk reported.
But Ferdinand feels United should make a move for Taremi, who has scored 14 goals in 20 appearances for Porto this season, while the 30-year-old impressed for Iran at the World Cup as he scored twice in the 6-2 defeat to England.
Taremi currently has a €60 million (£53m) release clause in his deal with Porto, which expires next year.