The ABC has been told local workers near the Arnhem Land township of Maningrida found a group of people on Tuesday. Another two people were found the following day, who are all understood to be in custody.
Newly appointed Shadow Home Affairs Minster Andrew Hastie says if confirmed, the arrival of Chinese nationals was a demonstration of the Albanese government's "underinvestment in our border security and defence capabilities".
While not confirming or denying the latest boat arrival, Home Affairs Minister Tony Burke has strongly criticised the response from his opposition counterpart.