Zhang said the high-speed trains, introduced in recent years, had raised the efficiency of rail travel and amenities while displacing a significant number of cheaper trains, which migrant workers used.

For example, when the ministry opened the high-speed line between Guangzhou and the Hubei city of Wuhan in December 2009, it cancelled 13 conventional services on the same route.

'Migrant workers can't afford the over-priced high-speed trains at a time of diminishing incomes and rising living costs due to inflation,' Zhang said.

The new service cuts travel time between those cities from 10 hours to a little more than three, but a ticket on the high-speed train costs at least 490 yuan (HK$577) - more than three times the price of a so-called hard-seat ticket.

The price controversy resurfaced when a photograph of a passenger in a carriage of a high-speed train heading from Shanghai to Nanjing, Jiangsu , was published late in July. A second-class seat for that trip cost 146 yuan, compared with 41 yuan for a hard-seat ticket on an ordinary train.

Train tickets are always in high demand during the Lunar New Year period as millions of people go home for family reunions, and the pressure on the railway system has been exacerbated by a rising number of migrant labourers in the past two decades.

The ministry said it expected to sell 230 million tickets - up 12.5 per cent year on last year - during the expanded 40-day sales period from today to February 25.

Zhang Yun, a worker at a Shenzhen electronics factory, said he had decided not to travel back to his hometown of Luoyang , Henan , to be with his wife and two-year-old child. He had failed to buy a ticket after several days of trying.

He said the availability of high-speed trains made no difference to him. 'The trains are not for people like me as they're almost as expensive as an air ticket,' said Zhang, who earns 2,000 yuan a month and sends much of that back home.

It was much the same story for Xu Heng , another factory worker in Shenzhen, who earns about 1,500 yuan. He had been planning to return to his wife's hometown of Huaihua , Hunan , on Friday, but ended up buying only one ticket, on a cheaper train, for his wife after queuing for more than two hours.

Now he said he was thinking of a trip home after the Lunar New Year.

'It's something you've got to get used to if you don't have much money to spend,' he said.

Zhang Yuanxin, the lawyer appealing for the discount scheme, said the ministry had not yet replied to the letter, but the contrast between the high demand for regular train tickets and the migrants' snub of high-speed trains was meant to send a message.

He said the discounts enjoyed by full-time students and children on regular train tickets should also be offered to them for high-speed train tickets.

'Does this mean that the fancy high-speed trains are something only for the rich?' Zhang asked.

The ministry budgeted 923 billion yuan in overall investment last year, but has failed to fulfil its promise to meet demand for affordable service, particularly during the Lunar New Year. Reports said the ministry promised in 2007 to solve the supply- demand problem by 2010 and vowed again in 2009 to have the job done by 2012.

Raw deal

High-speed trains cost more and lead to cheaper trains being phased out

The number of Guangzhou-Wuhan conventional services axed after the high-speed link started: 13