Scores of angry Electricity Supply Corporation of Malawi (Escom) workers in Blantyre on Thursday blocked the entrance to the Chichiri Power House in protest against unpaid bonuses.
This is the third time in 11 months for the workers to down tools at the sole power supplier over monetary issues.
The workers, mainly linesmen, prevented the corporation's vehicles from leaving the compound, threatening power connectivity.
The angry workers also pelted stones at journalists who attempted to take photographs of the scene.
Some workers interviewed at random told The Daily Times that the corporation's management in December last year promised to give each worker an ex gratia of K20,000 as a bonus for their service in 2012.
The workers argued that the money was promised to be given in January 2013.
"But come January, there was no money. So we have decided to down tools to force management to give us the money. We are suffering. We need this money to help us cope with the rising cost of living," said one of the workers, who opted for anonymity.
Escom Public Relations Manager Kitty Chingota said she was locked up in a meeting and promised to call back for an explanation.
In March last year, Escom workers also staged a strike in demand for 35 percent pay increase and threatened to switch off national-wide power supply.
The workers held another strike in July 2012 to force their management to raise their salaries.