A teenager has been arrested after a woman was allegedly stabbed multiple times as she sunbaked at a Queensland beach.

Queensland Police said the 23-year-old victim didn't know the 16-year-old alleged attacker, who stabbed her multiple times in the neck and body with a knife at Blacks Beach in Mackay at 12.20pm.

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The woman ran to a nearby construction site for help and the teen fled.

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Police said she was taken to hospital in a serious condition but her injuries are not life-threatening.

Queensland Police said: "A 16-year-old male has been taken into custody and is currently assisting with inquiries."