The sudden death of a two-year-old girl in suspicious circumstances in north Queensland is being probed by police.

Child protection detectives say the girl was already dead when she was brought to Mackay Base Hospital about 8.30pm on Thursday.

They said an autopsy would be conducted on Friday to determine the cause of her death.

“Investigations are ongoing and there is no further information available at this time,” police said in a statement on Friday.

-AAP