By day, he is a white-collar executive working in a technology firm. By night, he runs a website that provides ghostwriting services for academic papers.

'Our customers are very busy, and they don't have the time to write their own research papers. That is when they come to us,' the resident of north-eastern Changchun city, who wants to be known only as Mr Liu, told The Sunday Times.

Business has been good in the six months since he took over the company his friend set up. His team of five professional ghostwriters has helped churn out more than 50 academic papers.

While Mr Liu, 35, declined to reveal revenue figures, the current market rate for a paper is 650 yuan (S$134).

Businesses like Mr Liu's, though illicit, are on the rise in China. According to a study published last month by Wuhan University professor Shen Yang, the nationwide black market dealing in academic papers hit 180 million to 540 million yuan in revenue in 2007.

Three-quarters of the business is done through the Internet, the study said. Companies set up websites and aggressively promote their services through social networking sites, as well as advertising on search engines and online shopping sites.

Their clients include students, white-collar workers and even professors.

One student in the central Wuhan city, surnamed Chen, told a local newspaper that the money he spent on ghostwriting fees was well worth it: The academic paper that cost him 1,500 yuan helped him win a scholarship worth 10,000 yuan a year.

Some graduate students even pay for their entire theses, which they need in order to graduate, to be written for them. The Sunday Times found that a 20,000-word master's thesis costs between 3,500 and 5,000 yuan.

'The price depends very much on the subject matter and content,' Ms Pi, who works for the ghostwriting site www.lunwendx. com, told The Sunday Times.

'If the customer asks that the paper contain original data, then he will have to pay more. But sometimes, when the paper is too difficult to write, we will just turn him down.'

Professors and white-collar workers are also known to approach ghostwriting firms to help them write papers to secure promotions. The latter group usually consists of civil servants or employees of state-owned firms; some government agencies appraise employees partly through the academic papers they have written.

The alarming numbers have drawn a public outcry and put pressure on the Chinese academia, which has already been tainted by other problems, such as cheating and plagiarism.

A survey in Beijing in 2008 showed that 70 per cent of university students believed widespread plagiarism was taking place among their peers.

Analysts say universities will find it harder to police ghostwriting than plagiarism because ghostwritten articles are original.

'If the student refuses to admit that the paper was not written by him, it would be very difficult to prove otherwise,' said Professor Zhan Hao of the Northwestern Polytechnical University.

He suggests, however, that professors monitor their students more closely by meeting them at regular intervals to check on their progress in writing their theses.

Another measure, put forth by Prof Shen, is to reduce some of the pressure on university teachers to produce research papers.

'We should remove the quantity requirements and encourage them to write creative papers instead,' he said.

Mr Liu shrugs off the objections to his chosen sideline.

'I don't see ghostwriting as unethical,' he said. 'People don't always have time to do everything by themselves, so sometimes they pay to get some help. There's nothing wrong with that.'

This article was first published in The Straits Times.