The papers – which are either independent or back Mr Gbagbo’s rival, Alassane Ouattara – said their staff had suffered more than two months of physical threats.
Mr Gbagbo refuses to give up the presidency after November’s elections.
Mr Ouattara is widely seen as the winner of the poll.
Recent clashes between Mr Gbagbo’s and Mr Ouattara’s supporters have prompted the UN to warn the country is at risk of relapsing into civil war.
An armed rebellion in 2002 split the world’s largest cocoa producer between the north, held by the New Forces, and the government-controlled south.
‘Impossible situation’
The owners of the nine newspapers – which include leading titles Le Nouveau Reveil, Le Patriote and Nord-Sud – said they were suspending publication “until further notice”.
“Our journalists are constantly at risk of death,” the newspapers joint spokesman Dembele Al Seni was quoted as saying by the AFP news agency.
The papers also said they were being regularly fined by Ivory Coast’s media regulatory body, which remains loyal to Mr Gbagbo.
Mr Gbagbo has not publicly commented on the allegations.
Separately, the international media rights organisation Reporters Without Borders said that its “concern for press freedom in Ivory Coast is mounting by the day”.
“We offer our support to the privately-owned newspapers that are being hounded and threatened and have decided to denounce a situation that has become impossible for the press,” it said in a statement.
The organisation also condemned a recent lynching of a journalist employed by a pro-Gbagbo newspaper in Abidjan, where many supporters of Mr Ouattara live.
It also said the main transmission centre of RTI, the state-owned broadcaster controlled by the Gbagbo camp, had been recently attacked by Ouattara supporters in Abidjan.