RTE PRESENTER Joe Duffy says he found a threatening message directed at him over his coverage of Gerry Adams "chilling".
Sinn Fein said a fake party Twitter account attacking Mr Duffy was set up "mischievously" and is contacting the social media company to prevent further abuse of its logo.
The incident is the latest case of the party being embroiled in a fake Twitter account controversy following the Sean Gallagher affair during the presidential election.
The account, called 'Sinn Fein Corcaigh', appears to have been set up yesterday and had sent eight messages by the evening.
The bulk of the messages were about regular Sinn Fein campaigns, but there was a more sinister tone to a message about RTE's 'Liveline' and its presenter: "Gerry is a legend, let's get a hit out for Joe, boys."
Mr Duffy said he was worried by the incident as it was the first time he was threatened in this manner.
"I find this message chilling. Yes, it does worry me. It's the first time I have been threatened in this way.
"I'm hoping that Sinn Fein will distance themselves from these threats. I presume this is because Gerry Adams' name has been coming up a lot on the show lately," he said.
"He was mentioned again yesterday by Detective Garda McCabe's sister-in-law, Una Heaton, who was complaining about Mr Adams' twitter account.
"Someone may also have been unhappy with the radio documentary I did on the weekend about Thomas Niedermayer – the boss of the Grundig electronics plant in Belfast, who was kidnapped in 1973 and killed by the Provisional IRA, and whose wife Ingeborg and two daughters Gabrielle and Renata later committed suicide," he added.
Last night, Sinn Fein said it could "confirm absolutely" that the Twitter account was not a party account.
"As you are aware, there is no way to know who is running this bogus account nor to control its content.
"We are making approaches to Twitter to prevent abuse of the party logo," a party spokesman said.