Two international tourists have drowned while swimming at the Airlie Beach lagoon.

Emergency services were called to the popular north Queensland attraction just before 4pm on Sunday.

Airlie Beach lagoon.

A Queensland Ambulance Service spokesman said paramedics were called to treat a 5-year-old and a 30-year-old male, believed to be a father and a son.

The pair, understood to be Chinese tourists, were in a critical condition and had gone into cardiac arrest.