Moments after the start of his daily grind as a construction worker in northern China, Xia Donghai's world came crashing down with news that a terrifying earthquake had struck his hometown almost a thousand miles away.

With all communications down in Lushan county in the southwestern province of Sichuan, Xia's only way of knowing if his family had survived was to set off on an epic journey that would deliver either relief or tragedy.

"I am filled with terror, I do not know what I will find when I return to the family home," he told AFP, barging his way uninvited into one of the few cars to get through a police road-block on the edge of the disaster zone.

"I have no other way, I must continue my journey," he added, shutting the door defiantly behind him and sitting on the lap of a back-seat passenger, still in his work clothes and safety helmet, and in need of a wash.

"I have tried to call my family hundreds of times but I get no response," said the 48-year-old, frantic with worry in the hours after the disaster struck.

Xia is one of 230 million workers from China's impoverished inland provinces who have left their families behind in search of a better wage in the booming coastal areas.

Towns surrounding the epicentre of Saturday's earthquake -- which the US Geological Survey registered at magnitude 6.6 -- were said by domestic media to be one of the major labour export areas in Sichuan.

A teacher from Longmen townships's Chenyang Hope Primary School told the China Daily that more than half of his 88 students were "left-behind children" -- the offspring of migrant workers, left in the care of relatives.

Endless rows of houses that lay collapsed on the tiny village roads across Lushan were populated by elderly residents and women, looking after frightened children.

Yang Yue, a local official in Longmen, told AFP that there were many local families whose menfolk had left to work in other parts of China.

But he said the elderly, women and children were being supported by local relief agencies, and by the men who were returning in a steady stream following the quake, which has left at least 196 people dead.

"The vast majority of these migrant workers are returning home to help their families," Yang said, though he did not have figures on how many households were without men when the disaster struck.

Two women sitting outside a house in Longmen, tending a flame lit under a stove made from bricks that they had plucked from debris, said their husbands were working away.

"We have no communications, so we don't know if they are returning," one said, as they sat with an elderly woman and two children on wooden stools next to a makeshift tent crafted from wooden poles and canvas.

The last time Xia had visited home was Lunar New Year in February, when he spent the national holidays with his wife, daughter, son-in-law and grandson, who live in the kind of traditional stone house common to the region.

He told AFP that he spent 1,300 yuan ($210) -- a large chunk of his monthly salary of 3,000 yuan -- to pay for a flight from his workplace in Hebei province, 900 miles (1,440 kilometres) away.

Xia said the option of a far cheaper rail journey was out of the question, as he would have been racked with worry throughout the 27 hours it would have taken to arrive in the nearest major city, Chengdu.

Instead he took his first ever flight, and then hitch-hiked with emergency services from the Sichuan capital to Lushan, still clad in the heavy woollen jumper he wears in chilly northern China.

From there he joined thousands of people who had lined the streets attempting to make their way into cars which had been given access into the earthquake zone by authorities.

After climbing into a car, Xia believed he was on the final stretch to see his loved ones, but further road blocks and huge congestion further frustrated his efforts.

In the early hours in the busy centre of Lushan, he pleaded with a group of motorcyclists to take him home, his voice breaking as he tried to make himself heard above the roar of power generators in a town without electricity.

While rescue workers and media were often taken on the back of bikes, it appeared to be more difficult for a poor scaffold worker to complete the last few miles home.

"Stay safe," he said to AFP, as he ran off into the darkness of Lushan's unlit streets, seeking to bargain a ride with little more than the currency of his tragic tale.

The fate of his family remains unknown.