Man uses knife to steal taxi in Brisbane

A man has threatened a taxi driver with a knife and stolen his cab in Brisbane's north.

The man stole the taxi after he couldn't find anyone to pay his fare at an address in Strathpine around 3am on Monday.

Police tracked the taxi with GPS to a street in Lawnton where the man was spotted forcing a woman out of a car before speeding away with a male passenger who had also been in the vehicle.