Nearly six years after Greece's deadliest wildfire in the seaside resort of Mati, six people have been convicted of involuntary manslaughter and criminal negligence, the Athens criminal court said on Monday.

None of the politicians among the 21 people prosecuted over the disaster were convicted, sparking fury and dismay among relatives of the victims present in court, radio Skai reported.

Six people -- including the then head of the fire service -- received suspended sentences of up to 111 years each for the fire on July 23, 2018, which killed more than 100 people.

They were permitted by the court to buy off their sentences for up to 40,000 euros ($43,000) each).

The governor of the region of Attica and the mayors of districts in and around the seaside community of Mati, northeast of the capital, were all let off.

Reacting in court, families of the dead shouted: "Your court is an insult to the dead, the living and the truth", "There is no justice" and "You have no shame", state TV broadcaster ERT reported. Others wept.

Wildfires that broke out in and around Mati -- an area popular with holidaymakers -- spread with such ferocity that people burned to death in their cars because traffic jams prevented them fleeing.

Others drowned when they waded into the sea to escape the flames.

Many people escaped into the sea with just the clothes on their backs and had to wait several hours in the water for help to arrive.

It was local fishermen at first, not the coastguard or navy, who came to their aid.

In total, 104 people died and tens of others were injured.

- Poor urban planning -

The blaze destroyed an estimated 1,260 hectares (3,100 acres), the Athens Observatory said at the time.

The then government of left-wing prime minister Alexis Tsipras said that with winds blowing at a speed of up to 120 kilometres (75 miles) an hour, there had been little time for officials to mount an effective evacuation.

Police and the fire brigade gave different accounts.

Witnesses said at the time that residents had not been warned of the imminent danger.

Instead of being diverted away from the inferno, a number of motorists were accidentally directed towards the flames and were fatally trapped in Mati's narrow streets.

Prosecutors lodged criminal negligence suits against 21 officials from the fire service, port police and civil protection, as well as against local authorities.

Four senior officials, including then police minister Nikos Toskas and several police chiefs, resigned and fire fighters were forced to quit or move to jobs in other areas.

Experts have said that poor urban planning, including a lack of proper access routes and the construction of too many buildings next to combustible forest areas, contributed to one of Europe's worst wildfires this century.

The conservative government that succeeded Tsipras's administration pledged to introduce systematic evacuation plans as soon as wildfires approach populated areas.