Amnesty International has urged MPs in Trinidad and Tobago not to vote to allow capital punishment to resume.
On Friday, MPs are due to debate a constitutional amendment that would remove some obstacles to executions.
Trinidad's government says capital punishment, not used since 1999, is needed to tackle the high murder rate.
Rulings by the London-based Privy Council, the final court of appeal for some Caribbean nations, make it more difficult to use the death penalty.
One of the key decisions was in 1993 when the Privy Council ruled that the death penalty could not be carried out more than five years after sentencing.
In many cases, it takes several years to exhaust the appeals process, meaning most death row prisoners have their sentences commuted to prison terms.
The government has therefore proposed amending Trinidad's constitution in order to be able to overturn rulings by the Privy Council.
Members of parliament will consider such a bill during Friday's parliamentary session.
Prime Minister Kamla Persad-Bissessar has called the death penalty "a weapon in [our] arsenal" to fight the murder rate.
"In every tear shed by relatives of every murder victim, there is a desperate cry for justice. Mothers have lost their sons and daughters, children are left motherless and fatherless. Homes left without incomes, families destroyed and forced into poverty," she said.
Human rights group Amnesty said it was urging MPs not to back the bill, and should instead tackle the root causes of violent crime while reforming the police and justice systems.
"We are extremely concerned that the new bill would allow for someone to be executed within a short period after a sentence is passed, not allowing for proper appeals, and that others could be kept on death row for years on end," said Amnesty researcher Chiara Liguori.
There are more than 40 people currently on death row in Trinidad and Tobago.
Capital punishment enjoys widespread public support in the country, as in other Caribbean nations.
Last year, the murder rate in Trinidad and Tobago was 36 per 100,000; UN figures for 2008 for Jamaica showed a murder rate of 59. In the US, it was just more than five.