SYDNEY, Australia — If money talks, it was the stacks of crisp $100 bills that spoke loudest. An Indonesian smuggler said the Australian authorities had stopped his boat at sea and given him and his crew the cash, more than $30,000, to take his cargo of 65 migrants to Indonesia.

The allegation, which the Australian government has not denied nor explicitly admitted, was the latest indication of a hardening of Australia’s immigration policy under Prime Minister Tony Abbott, which critics say has at times veered into illegality.

If the boat captain’s story is true, the incident may have violated Australian, Indonesian and international laws against smuggling, bribery and the treatment of asylum seekers.

“Australia is moving to ever more radical measures to avoid our international obligations,” said Hugh de Kretser, director of the Melbourne-based Human Rights Law Center. “But the world is watching.”