Indonesian authorities arrested a Malaysian pilot for allegedly smuggling at least 26kg of the synthetic drug MDMA while being on the job, the customs office said on Friday.

Officials said the pilot, identified by the initials MSO, 39, was arrested on Wednesday at the main airport of the capital city of Jakarta.

At least 14 bags of ecstasy – more than 70,000 pills – and four grams (0.14oz) of meth were found in the pilot’s suitcase, customs officials said.

The methamphetamine was found in his hand luggage and reported to be for his personal use, officials said. The pilot is believed to have flown under the influence of multiple drugs, they said.

While the airport customs office did not specify which carrier the pilot was working, the flight number suggested it was a Malaysia Airlines plane.

He flew the plane from Kuala Lumpur to Jakarta, customs officer Hengky Tomuan Palindungan Artionang.

“The results of his urine test came back positive for meth, MDMA, and cocaine. So, at the time of the flight, he was under the influence,” the official said, speaking to reporters in Jakarta.

He added: “What concerns all of us is that this person’s profession is a pilot, and at the time he arrived, he had just flown that plane from Kuala Lumpur to Indonesia.”

A urine test of the pilot right after the flight confirmed he was under the influence of cocaine and synthetic drug methamphetamine, Mr Hengky said.

The pilot is believed to have brought MDMA in a suitcase to Jakarta for an unidentified person with the promise of a reward worth around 50,000 ringgit (£9,092), the official said.

He has now been named a criminal suspect for being a courier of a drug which is covered under Indonesia’s strict drug laws.

The accused told investigators that this was the time he attempted the smuggling of banned drugs, with the previous instances being to Indonesia earlier once and to Malaysia.

If convicted, the accused can be punished to death penalty or life imprisonment under Indonesian law.

The southeast Asian nation has some of the world’s toughest anti-drug laws, including the death penalty for traffickers. However, it has abstained from executions for several years.

In 2015, an Indonesian court ordered the execution of two Australian nationals in the Bali Nine drug ring for attempting to smuggle heroin out of the resort island of Bali.

Malaysia Airlines declined to comment on the case as it was under investigation, but said it does not tolerate any form of misconduct and is currently conducting an internal review into the matter.

The company added that it will cooperate with relevant authorities.