Sydney: A 17-year-old boy has been charged with reckless wounding after a man was stabbed in the back in Sydney's inner west on Saturday.

Police say the 58-year-old victim was taken to hospital in a critical but stable condition after the incident in Dulwich Hill just after midday.

The teen was arrested at a home in Gray's Point on Saturday night and will appear in a children's court on Sunday.

In a separate incident also on Saturday, a 16-year-old boy was seriously wounded after he was stabbed several times in north-west Sydney.

Police say the teenager was taken to hospital in a serious but stable condition after the incident in Kellyville on Saturday night.

AAP