At least two correspondents to this newspaper were taken in for questioning by the military to warn them off.
Soldiers also took in a trade union leader after comments he made at a private club on army commander Commodore Voreqe Bainimarama.
A regular correspondent to the Letters to the Editor column said a twin cab with around six armed soldiers visited his home in Lautoka around 10am and asked for him.
"My wife said that I was at work and half an hour later they picked me up from work and took me down to the base here in Nadi,'' he said.
"They asked me about my letters and said that this is a verbal warning.
"I explained to them that my letters are my views and I do not incite, nor do I condone any stupid ideas.
"I also explained that I've written many letters on different topics and not necessarily targeting the army."
He said he had not been threatened in any way and the soldiers were friendly and courteous, saying they were carrying out orders from the headquarters.
The wife of another regular writer to the open column said her husband was arrsted at work.
"My husband was arrested at 11am and till now I have not heard from him," she said in an email to The Fiji Times at 4.30pm.
It could not be determined last night whether the husband had been released by the army. Efforts to get a comment from the wife were unsuccessful.
Fiji Times publisher Tony Yianni said the letters had presented reasonable opinions.
"We have given an undertaking to publish responsibly and not to publish anything that could incite unrest," Mr Yianni said.
"Neither of these letters could be considered as anything other than reasonable debate, given the situation in Fiji at the moment.
"Commodore Bainimarama promised to uphold media freedom but these actions restricts the freedom of speech, which is protected by Fiji's Constitution."
Army spokesman Major Neumi Leweni said yesterday he was not aware of the two incidents.
Meanwhile, unionist Kenneth Zinck was taken in for questioning by the military on Wednesday night after he publicly called military leader Commodore Bainimarama names.
Mr Zinck, who was at the United Club when he was arrested at around 9pm, said he was seated with friends at the bar when he blurted out a name to Commodore Bainimarama who was on television at that time.
He suspected that a relative of Commodore Bainimarama, who was drinking nearby, must have tipped off the soldiers.
Mr Zinck said at Queen Elizabeth Barrack, he was made to run around a sports field while four soldiers ran behind him with guns pointed to his back.
"Then they made me stand under the spotlight while they stood behind it so that I couldnt see their faces and warned me not to speak out against their commander again and for me to watch out. That was followed by Get Out," Mr Zinck said.
He said he was escorted out the military camp where he hailed a taxi and returned to the club.
Major Leweni could not confirm or deny the incident.