'Half the respondents believe Hong Kong's news media practise self-censorship, mainly because of their hesitation to criticise the central government, but don't think this is so when they criticise the HKSAR government,' programme director Dr Robert Chung Ting-yiu said.

Fu King-wa, a research assistant professor at the university's journalism and media studies centre, said the 'marginal increase' might have been due to the chief executive elections in the month before the poll.

'In that month, many of the news media ran articles taking stances which the public might have thought indicated those organisations had internal preferences,' he said.

The percentage of people who believed news media practised self-censorship was four percentage points higher than seven months ago, but four lower than a year ago.

Top news items during this latest survey included those on ousted Chongqing party boss Bo Xilai and restrictions on mainland women giving birth in Hong Kong.

When the survey was conducted seven months ago, headline items included HSBC's plan to lay off 3,000 employees and former deputy secretary for labour and welfare Roy Tang Yun-kwong's appointment as director of broadcasting at RTHK. Last year, news of the government's plan to sell 12 development sites and China's inflation and economic growth were big items.

The most recent poll also found that 63 per cent of respondents believed local news media abused or misused the freedom of the press, up six percentage points compared with seven months ago.

Fu said the figures only provided an indication of people's impressions. It would take separate studies to determine the reality of self-censorship and freedom of press abuses.

Chung said only 40 per cent considered the media to be responsible in their reporting.