The spate of arrests of Australians – as many as eight in recent months – prompted the Department of Foreign Affairs and Trade to issue atravel advisory on Thursday warning travellers of the severe drug laws in China, while also noting the "substantial risks involved in carrying parcels for others which may conceal narcotics".

While DFAT says it does not intend to reveal specific details of the Australians arrested, Fairfax Media has learnt of strong concerns that at least some of the Australians involved could have fallen foul of business-related scams which in turn have led to the suspects – unwittingly or otherwise – becoming drug couriers.

"We have some concerns that there may be a pattern in the cases of some of the individuals being arrested," a DFAT spokesman said on Friday.

It is understood the issue had been raised in the most recent bilateral meeting between Foreign Affairs Minister Julie Bishop and her Chinese counterpart Wang Yi in Sydney last week.

One source said while there have been previous unreported instances of Australians being arrested in China for drug offences, the current spate was "unheard of" and "highly unusual".

The barrage of arrests has stretched the workload of the consulate in Guangzhou, the provincial capital, with diplomats not usually involved in consular assistance also being pulled across to help with consular meetings and dealing with families.

Guangdong authorities launched a spectacular drug raid in December as part of the broader anti-drug sweep codenamed "Operation Thunder". More than 3000 paramilitary and police swooped in helicopters and speedboats in 109 separate raids which culminated in the confiscation of more than 3 tonnes of methamphetamine, also known as 'ice', and 23 tonnes of raw materials. Almost a hundred foreigners, mostly of African background, were arrested in one raid alone, according to state media.

In a separate, high-profile arrest, 71-year-old Japanese senator Takuma Sakuragi – who also runs a private business in China – was detained and charged with drug trafficking in October after being caught with 3.3 kilograms of methamphetamine.

Mr Sakuragi, who pleaded not guilty to the charges in court last month, said he was convinced to travel from Nagoya, Japan to sign "certain documents" in Guangzhou to recoup $US701,000 that he had lost from investments. He said he had no knowledge of the drugs hidden in the retractable handles and soles of shoes in his suitcase, which was given to him by his business associates from Nigeria and Mali.

China's harsh drug laws state that people found guilty of possessing more than 50 grams of meth or heroin could face the death penalty. In 2010, four Japanese nationals were executed by China on drug-trafficking charges. Two Koreans were executed on drug distribution charges last month.

Chinese foreign ministry spokeswoman Hua Chunying on Thursday acknowledged there were a "number" of Australians detained in China on drug charges, and that the cases were being dealt with "in accordance with the law". She said drug crimes were universally recognised as a serious threat to society, while adding that China's drug laws did not distinguish between nationalities.

pwen@fairfaxmedia.com.au