A motorcycle rider has died after colliding with a boat and trailer in Pinjarra.

It happened near Butler Street just after 5pm yesterday.

Police say the boat was being towed by a white Toyota Hilux.

The rider, a 37-year-man suffered critical injuries and died at the scene.

Major Crash investigators would like to speak with anyone who saw the crash or either vehicle beforehand.

Witnesses can call Crime Stoppers on 1800 333 000.