Eight media organisations said the law, passed late on Monday night, was “draconian” and undermined the existing code governing the industry.
The Togolese authorities were attempting “to muzzle the press”, they charged, urging journalists and human rights activists to mobilise and fight for press freedoms.
According to the new provisions, publishing false, malicious and potentially defamatory information, causing or raising the likelihood of a breach of the peace can now be punished with six months to two years in jail.
It also provides for a fine of between 500,000 and two million CFA francs ($840/760 euros).
The media and communication law, adopted in August 2004, decriminalised media infractions and subjected any breaches to fines only.
The revision is part of a new penal code designed to upgrade the existing document that dates back to 1980 and which contained a number of omissions.
Journalists and media bodies in Togo have previously criticised government attempts to stifle press criticism as heavy-handed.
In May, dozens of journalists staged a sit-in near police headquarters in Lome to demand the release of a colleague arrested for allegedly defaming the security minister.
Media rights watchdog Reporters Without Borders ranks Togo 80th in its Press Freedom Index.
Independent media, particular online publications, had been blocked since the contested re-election of President Faure Gnassingbe in April, the group added.