Police have arrested an Indonesian couple and seized 63 slabs of compressed marijuana worth RM123,000, an official said on Tuesday.

Rodwan Mohamad Yusof, a local police chief, said a 34-year-old Indonesian man and a 23-year-old woman were detained last Thursday in Klang, west of the capital Kuala Lumpur, for alleged drug trafficking.

"The house that they have rented since a year ago is also believed to have been used to keep drugs for distribution in the Klang Valley," he was quoted as saying by the Bernama news agency.

Rodwan said the couple were being investigated under Section 39B of the Dangerous Drugs Act 1952, which carries the mandatory death penalty on conviction.

Malaysian laws set a mandatory death sentence for anyone caught with 200 grams or more of marijuana.

More than 100 people, a third of them foreigners, have been hanged for drug offences in Malaysia since the law was introduced in 1981, but the lucrative drug trade continues to lure traffickers.