TRIPOLI - International Criminal Court (ICC) envoys in Libya were to visit on Tuesday four colleagues who were detained in the western hilltown of Zintan, officials sources said.

"The ICC delegation is on its way to Zintan," said Ajmi al-Atiri, commander of the brigade that detained Australian lawyer Melinda Taylor and three of her colleagues following a meeting with Moamer Gathafi's son, Seif al-Islam.

Ahmed al-Jehani, Libya's envoy to the ICC, confirmed the visit.

"The other (ICC) delegation is on their way to them," Jehani said.

"An ICC lawyer is part of that delegation," he said.

Taylor and her team was transferred to a prison in Zintan on Sunday, the same day that a new ICC mission arrived in Tripoli to negotiate with the Libyan authorities.

The ministry of defence oversees the prison where the ICC envoys are held, Atiri said. He said the men in his brigade, Abu Bakr al-Sadiq, have all registered with the ministry of interior or defence.

Tripoli accuses Taylor of exchanging documents that represent a threat to national security with Seif al-Islam, who has been held in Zintan since his capture November 19 last year.

The Hague-based tribunal has called for their "immediate release."

A report released on Tuesday said Australian lawyer will be freed if she reveals the whereabouts of the country's most wanted man, a key player in the former regime of Moamer Gathafi.

Libyan government spokesman Mohammed Al-Hareizi told the Australian Broadcasting Corporation that Taylor would be freed if she gave them information on Ismail.

"We want this guy. It is very important to catch this guy because this guy is very, very, very danger(ous) for us," he said.

Al-Hareizi claimed Taylor had met with Ismail given that she had a letter from him. "That means she (had met) him (somewhere), I don't know where," he said.

Asked whether the 36-year-old Australian would be released if she revealed where Ismail was, he replied: "Yes. Yes."

"We don't have anything against this woman. Just we need some information from her, after that she will be free," he added.

The ABC said that Taylor had interviewed Seif while an observer was present and apparently did not know that the observer was able to understand English perfectly.

"She said very bad words about us and she spoke with Seif, she tell him: 'You are not guilty'," Al-Hareizi said.

Al-Hareizi insisted that Taylor was "in safe hands" but Australian Foreign Minister Bob Carr said he was concerned at reports that the four members of the ICC team had been moved from house arrest to an unidentified prison.

Australia, which has called for Taylor and her colleagues to be released, said it was essential that Libya grant immediate consular access to the four.

"The Australian government is very concerned that Ms Taylor has reportedly been moved, and has so far not been permitted (to) contact with either a representative of the Australian government, the ICC or her family," Carr said.

The ICC team was in Libya to help Seif choose a defence lawyer. The Hague-based ICC wants to try Seif, 39, for crimes against humanity.