Man to face court over 3 Sydney stabbings

A 21-year-old man accused of stabbing three teenage boys at a house party on Sydney's upper north shore is expected to face court on Monday.

The man spent Sunday night in police custody after being refused bail charged with three counts of wounding with intent to cause grievous bodily harm as well as a weapons offence.

A 16-year-old boy is in Royal North Shore Hospital where his condition on Sunday night was critical.

Two other boys, aged 17 and 18, were understood to be stable after also suffering stab wounds.

Police and paramedics descended on Heydon Street in Warrawee just before midnight on Saturday after reports that the three young males had been stabbed.

Officers set up a crime scene and hunted the alleged offender, who was nabbed near Hornsby Police Station about 9am Sunday.

He is due to appear at Hornsby Local Court.