Watergardens Shopping Centre, Melbourne rocked by second alleged knife incident ... trends now

A teenage boy allegedly threatened patrons with a machete at a busy Melbourne shopping centre, only hours after a separate alleged knife incident sent the mall into lockdown.

Police allege the 15-year-old boy was yelling threats while armed inside the Watergardens Shopping Centre in Melbourne's west about 7.30pm on Friday.

The teen, who was detained by security, has since been arrested and charged with making threats to kill and being armed with criminal intent.