A SINGAPOREAN man who swallowed more than A$500,000 (S$640,900) worth of heroin and then tried to smuggle it into Australia, was jailed five years by a court in Brisbane on Tuesday.

Teck Boon Ng, 40, had 91 packets of heroin in his stomach when he was arrested at Brisbane International Airport on June 27 last year, The the Supreme Court in Brisbane was told.

He pleaded guilty on Tuesday to one count of importing a marketable quantity of a border controlled drug, according to a report carried on news.com.au.

Commonwealth prosecutor Paul Huygens told the court that Ng had arrived on a flight from Hong Kong and was grilled by Customs officers after looking 'nervous'.

He quickly admitted to having swallowed a large amount of heroin before boarding the flight.

He was arrested by Australian Federal Police and spent two days in hospital while he passed out all the packages, said the online report.

The court was told Ng had swallowed almost 500g of powder, and that the pure weight of the heroin was 286 gm. The drugs had an estimated street value of A$572,000.

Defence barrister Simon Lewis said Ng had agreed to courier the drugs to Australia out of desperation for money.

Mr Lewis told the court his client had travelled to Hong Kong in search of work but had been lured into becoming a mule with the promise of a US$5,000 payment.

He was given just US$400 and a mobile phone before leaving for Australia, and told immigration officials the purpose of his trip was for a holiday.

The five-year jail term is with no parole.