During a rare Sunday sitting of Parliament to debate the extension, Prime Minister Kamla Persad-Bissessar said the state of emergency has prevented "a criminal uprising of untold proportions" in the southern Caribbean country off Venezuela's coast.
The government first issued a state of emergency last month following a spike in violent crime that saw 11 murders in 48 hours.
The measure involves an 11 pm to 4 am curfew and gives security forces enhanced powers to search suspects and seize property without a warrant. Police and soldiers are patrolling crime hotspots in the two-island nation of 1.2 million people.
The new time comes close to the suggestion made by businesses that the lockdown be amended to 12 am to 5 am.
"The state of emergency has worked," Persad-Bissessar told the House of Representatives, who extended the measure until December because they agreed the crime crackdown was still incomplete. "Rest assured the crisis has been averted."
Speaking to The Associated Press on Monday, Foreign Affairs and Communications Minister Suruj Rambachan said the government is prepared for any "backlash" as a result of the extension.
"We are ready for any backlash that the criminal element may wish to engage in. We are aware that the criminal element will not be pleased by the state of emergency but the defence force and the police are ready to deal with them," Rambachan said.
In coming weeks, Rambachan said the government will launch initiatives aimed at "preventing or discouraging the less-fortunate citizens from engaging in a life of crime."
Among the new measures are education programmes targeting youngsters in deprived communities and a fact-finding team to probe the root causes of criminality.
On the streets of Port-of-Spain, the country's capital and biggest city, residents expressed mixed emotions about the extension of the state of emergency until December.
"I am happy for the extension, crime is down. Something must be done to stop the crime in T&T," said Sandra Davis, an unemployed resident.
Roger Lezama, a security guard, said he believes the state of emergency is a "waste of time".
"There is no freedom in T&T anymore. My life is a curfew. It won't stop crime. What will happen when the state of emergency is over? More crime and more crime," Lezama told the AP.
Opposition lawmakers have criticised Persad-Bissessar's crackdown for failing to net the "big fish" in Trinidad's underworld.
The prime minister has blasted opposition figures in former Prime Minister Patrick Manning's administration for forging an "unholy partnership" with gangsters through the years, alleging that state resources were dispersed to troubled neighborhoods via criminals who the People's National Movement government had recognised as "community leaders."
"We do not negotiate and wine and dine with gang leaders at hotels, as that last administration did ... just to stay in power," Persad-Bissessar was quoted as saying in the Trinidad Express newspaper.
She said the state of emergency has greatly reduced serious crime and resulted in 1,356 arrests as of Sunday. She said 420 arrests were gang related and 33 were due to homicide charges.