The Times of Oman on Saturday reported that Attorney-General Husain bin Ali al-Hilali had said the interrogation of the detainees were nearly complete and a trial in a special court would begin soon.
"The statement stressed that all the guarantees given by the Basic Law of the State (Oman's first written constitution issued in 1996) had been taken into consideration and implemented," the paper said.
Omani media coverage
"The suspects would be allowed to engage lawyers to defend them in the court as per the law, and the sentences issued against them would be announced in the media."
The statement did not specify how many suspects were to go on trial.
It said only that "a group of citizens were arrested for being linked to a banned secret organisation" and that the authorities had gathered evidence confirming the existence of the unnamed group.
Sources in the Western community in Oman said last month that the arrests, made in early January, involved around 20 people who were detained on suspicion of setting up an organisation that threatened the country's national security.
Wave of arrests
Relatives of the detainees earlier said more than 100 people, including prominent academics, were being held following a wave of arrests on 9 January.
Information Minister Hamad al-Rashdi said the arrests were prompted by "the setting up of an organisation aimed at harming national security, which is one of the red lines".
"The suspects would be allowed lawyers to defend them in the court, and the sentences issued would be announced in the media"
Times of Oman
The arrests were apparently carried out in the interior of the country, a traditional stronghold of the dominant Ibadi Muslim sect.
Family members also said security forces intercepted an arms shipment from Yemen, al-Qaida chief Usama bin Ladin's ancestral homeland.
But the detainees are said to be mainly Ibadis, not Sunni Muslims like bin Ladin's supporters.
Insurgents associated with al-Qaida have been blamed for a wave of bombings and shootings in the region which began in Saudi Arabia in May 2003.
Kuwait, another oil-rich Gulf state, was rocked by a series of deadly gun battles between security forces and suspected Islamist militants in January.
Last week, a car bomb killed a Briton and wounded 12 other people in Qatar, raising fears that Islamist unrest was spreading around the Gulf.