Mass murderers such as Ian Brady have forfeited their right to life, Gregory Campbell said yesterday.
The East Londonderry DUP MP said there were times when the death penalty was appropriate.
He acknowledged there was little chance of the reintroduction of execution in the UK because of the European Convention on Human Rights but blamed a cosy consensus of politicians for denying the people their wish.
"There are times when the death penalty, operated within a robust legal framework, is an appropriate form of punishment," he said.
"We can all think of mass murderers who through their evil acts forfeited their right to life.
"I have no compunction at all in saying that someone like Ian Brady, the Moors Murderer who murdered five innocent children, has forfeited their right to live through their actions."
Mr Campbell was addressing a Westminster Hall debate calling for a world-wide ban on capital punishment.
He added polls regularly showed a majority in the UK favoured the death penalty for crimes like premeditated murder.
Amnesty International criticised Mr Campbell.
Northern Ireland director Patrick Corrigan said: "Gregory Campbell is plain wrong in thinking that the death penalty has any place in a 21st-century justice system, whether in the UK or any other country.
"He should not be defending the cruelty of nations like Iran, Saudi Arabia and China in continuing this barbaric practice.
"Beheadings, electrocutions, hangings, lethal injections, shootings and stonings have no place in the modern world."
SDLP Justice spokesman Alban Maginness was appalled.
"I think there is a well-established view that capital punishment in the western world is regarded as abhorrent and unlawful and inappropriate," he said.
"Capital punishment doesn't work. Quite apart from that it goes against the modern view of human rights and indeed there's a protocol attached to the European Convention on Human Rights outlawing capital punishment."