Hundreds of thousands of workers in Turkey and Syria have lost their livelihoods due to the earthquake, the United Nations said Tuesday, as it called for urgent support to rebuild businesses.

The earthquake has had a devastating impact on workers and enterprises, the UN's labour agency said.

The International Labour Organization calculated that in the 11 affected provinces in Turkey, the hours of work lost were the equivalent to the work done by around 657,000 workers.

In Syria, in the five affected governorates, it is estimated that around 170,000 workers have temporarily lost their jobs due to the destruction, the ILO said.

The 7.8-magnitude quake that struck on February 6, and its aftershocks, killed more than 55,000 people across southeastern Turkey and parts of war-torn Syria.

"People can only begin to rebuild their lives if they have rebuilt their livelihoods," said ILO chief Gilbert Houngbo.

"We owe it to those who have lost so much in the earthquake to ensure that the principles of social justice and decent work are firmly embedded in the recovery and reconstruction process."

The ILO calculated that the average affected worker in Turkey would lose around $230 a month "as long as the situation continues".

Overall, the crisis is estimated to reduce the take-home labour income of the affected region by around $150 million per month.

Besides job losses, the ILO warned of increased risks to occupational safety and health in Turkey, as well as child labour.

The temporary loss of 170,000 jobs in Syria has led to total labour income losses equivalent to at least $5.7 million a month, the ILO said.

The job losses have directly affected around 154,000 households and more than 725,000 people, the agency said.

Around 35,000 micro, small and medium-sized enterprises have been affected.

"The loss of these businesses goes beyond the loss in incomes and encompasses the cost of the physical damage to their infrastructure, such as buildings, equipment, and inventory," the ILO added.

In Turkey, the ILO said it was helping Turkish business organisations and trade unions to function and provide critical services, with initiatives on seasonal agricultural workers, child workers and refugees.

In Syria, the UN agency is providing grants to help support affected workers and businesses.