A 16-year-old boy has been charged over the stabbing of a teenager in suburban Armadale.

Police say the 16-year-old victim was stabbed after refusing to hand over a trail bike as payment for an outstanding debt.

It is alleged both were armed with knives and one was stabbed under the right shoulder blade.

Police say the boy rode to a relative's house in Kelmscott, before he was taken by ambulance to hospital for treatment.

The other boy has been charged with causing grievous bodily harm.

Meanwhile a 16-year-old Waikiki boy has been charged with unlawful wounding after allegedly striking a 17-year-old with a glass bottle.

Police say the boys were at a house party in Diamantia Way in Rockingham, when a fight broke out between the pair just before midnight.

The injured teenager was treated at Rockingham hospital for a gash to the head.