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Charles Gnanakone, a Sri Lankan Tamil businessman who now holds an Australian passport, was arrested last week under emergency regulations, they said.

Gnanakone, 60, was held in the wake of media reports that he had assured Kadirgamar that he wouldn't be killed as long as he remained foreign minister. Kadirgamar, also a Tamil, was known to Gnanakone.

The government has also tried to link Gnanakone to the main opposition United National Party in an apparent bid to discredit the opposition ahead of the November 17 presidential elections.

The Australian High Commission in Colombo said they were extending consular assistance to Gnanakone whose arrest had been informed to them officially.