Zambian President Edgar Lungu has vowed to take "stringent action" against those he suspected of having caused an inferno that razed the biggest market place in the capital Lusaka on Tuesday, reports say.

Zambia's biggest market was reportedly burnt down early on Tuesday "destroying the livelihood of its many traders".

Police were still investigating the cause of the fire, which left some of the traders in tears, as they lost most of their goods.

According to BBC, some people at the gutted market said they suspected it was caused by an electrical fault.

But Lungu, who jetted back into the country from the African Union summit in Ethiopia on Tuesday, maintained that the market was deliberately set on fire in an act bordering on "economic sabotage", the report said.

He "vowed to bring the suspected arsonists to justice".

In a series of Tweets, Lungu described the the incident as "economic sabotage".

Meanwhile, according to Africa News, the country’s largest opposition the United Party for National Development (UPND) has called for thorough police investigation, adding that the incident shouldn’t be politicised.

In a statement, the UPND said that "it is too early to speculate".

"It is in the same vein that we call upon those that find comfort in politicising such tragedies to lay off their hands and let independent professionals do their job unhindered," the UPND said.

Security wings are working hard to investigate all possible areas of wrongdoing in the fire incidence. The nation will be kept informed.