"Worker Antonio Jose Pita Martins, 55, died after an accident happened when he was dismantling a crane in the area outside the Amazonia Arena," the Sports Ministry said in a statement.
Martins, who was Portuguese, was the third person to die while working on or near the ground and the sixth to perish while preparing the 12 stadiums for this year's tournament.
The Amazonia Arena, which should have been completed in December according to FIFA's original deadline, is behind schedule and workers were rushing to get the job finished.
Amazonas state governor Omar Aziz cancelled a planned visit to the stadium because of the accident, an official statement said.
The first fatal accident at the stadium was in March last year and a second worker died in December when he fell from the roof after a cable snapped.
One worker has been killed in Brasilia and while two people died in Sao Paulo after a crane collapsed at the stadium which will to host the opening game on June 12.
Preparations for the World Cup have been plagued by delays, accidents and cost overruns.
Last year's Confederations Cup was staged amid nationwide street protests with public spending on stadiums among the protestors' many grievances.
The latest death may add to concerns that safety is taking a back seat as the host cities rush to finish their arenas.
Six stadiums were used in last year's Confederations Cup and one more has been completed since then. Another five are still not ready.
Manaus, located at the heart of the Amazon rain forest, will host four games, including the high-profile encounter between England and Italy.
It will also stage the United States v Portugal, Cameroon v Croatia and Honduras v Switzerland games.
Switzerland coach Ottmar Hitzfeld last month complained about playing in the heat and humidity of Amazon basin, saying the decision to stage matches in Manaus was "almost irresponsible."
- Sports & Recreation