A majority of US voters know little about Demoratic presidential candidate John Kerry and want him to make his stand clear on key issues like economy, Iraq and war against terrorism, a new poll said.

The poll, conducted by Washington Post-ABC News, suggested that 54 per cent of the voters were unfamiliar with  the Massachusetts senator's positions against only 25 per cent  who felt the same about Republican President George W Bush.

In barely a month, Kerry has lost ground to Bush on every top voting issue in the November 2 polls and a growing proportion of voters considered the President as the candidate who most closely shared their values, the survey said.

"In virtually every measure tested Kerry's image has eroded in recent weeks. He has lost his double-digit advantage as the candidate viewed by voters as more honest and more understanding of their problems," the latest survey conducted just ahead of the Democratic National Convention in Boston which began on Monday.

Even among Democrats, 46 per cent said they were unsure what Kerry stands for.

The proportion of voters who rate Kerry as "too liberal" has increased slightly, from 36 per cent in June to 40 per cent and 49-43 per cent see Bush as the candidate who better reflects their values.

Bush was seen as better qualified than Kerry to keep the US safe and secure by a 54-38 percent margin -- wider than one month ago when it was 54-40 per cent, the poll said.

By increasing margins, the president is seen as better able to deal with Iraq and the war on terrorism and taxes. On two key issues in which Kerry had the advantage two weeks ago, education and the economy -- both candidates were tied, the poll said.

The poll found that Kerry and Bush remained virtually deadlocked, with 48 per cent of registered voters supporting the Republican and 46 per cent the Democrat.

A total of 1,202 people were interviewed July 22-25 for the poll, which had a margin of error of plus or minus three percentage points.