The heroin was allegedly found inside four medium sized black cases of Maj-Jong and Domino tiles.

"The tiles appeared to be of poor quality and were subjected to further tests by Customs and Border Protection Officers," an Australian Federal Police spokesman said in a statement on Saturday.

Following a Mah-Jong tile being drilled, a sizeable amount of heroin was located, police say.

The discovery has led to a 30-year-old Ashcroft man, who arrived in Sydney on November 20 from Vietnam, being arrested.

It will be alleged in court he concealed approximately 5.5 kilograms of heroin worth an estimated street value of $1.25 million.

The man was charged with importing a commercial quantity of a border controlled drug into Australia, and will appear at Parramatta Local Court on Saturday.

The maximum penalty for the offence is 25 years imprisonment and/or a $550,000 fine.

AAP