There are calls for a central information point for would-be students
Poor white men are the most under-represented group in England's universities, a spending watchdog says.
Poor school results are the main reason but not enough was being done to publicise the financial help available, the National Audit Office reported.
There had been some progress since 1998 in widening participation.
But only two percentage points more 18 to 20-year-olds from poor homes in England were in university than five years ago, despite a £392m campaign.
The report's authors said "some progress" was being made in encouraging under-represented groups to go into higher education, but criticised "incomplete data" on student background, saying it hindered accurate assessment of which groups were under-represented.
The NAO reported that "people from lower socio-economic backgrounds make up around one half of the population of England, but represent just 29% of young, full-time, first-time entrants to higher education".
In the past 10 years, young people living in deprived areas had experienced an increase in participation of 4.5 percentage points compared with an increase of 1.8 percentage points in the least deprived areas.
"White people from lower socio-economic backgrounds, both men and women, are the most under-represented group", it said, although it added that there were other groups whose participation it was difficult to assess because of incomplete data.
Tory MP Edward Leigh, who chairs the Commons public accounts committee, said the lack of guidance to would-be students was the most worrying finding of the inquiry.
"Efforts have been made to support all who wish to continue into higher education and some progress is being made to that end," he said.
"But after five years and the spending of £392 million, participation by young working-class people has increased by only two percentage points.
"It is disappointing, if somewhat predictable, that the newer universities are having more success than Russell Group universities in broadening access.
"There is an incomplete picture on which initiatives to widen participation work. But the biggest concern is the inadequate advice and guidance for people who have the ability to progress to higher education, but think 'university isn't for the likes of me'."
The NAO report called for a more rigorous assessment of progress towards the aim of opening universities up to students from poorer backgrounds and the creation of a single source of information for potential students.
And universities which performed badly should face sanctions, it said.
England's Higher Education Minister, Bill Rammell, said the report showed progress was being made and he backed its recommendations for future action.
New government figures showed university participation in the bottom four socio-economic groups had increased from 17.5% to 19% between 2002 and 2006, he said.
"This clearly demonstrates that the breadth of activities that the government has put in place are working.
"Ministers share the NAO's analysis of the next steps to be taken.
"In the last year we have encouraged universities to form links with schools to raise standards, launched a plan to make higher education available in 20 more towns and cities, called for a combined widening participation strategy for each university, said that all universities should publish transparent and accountable admissions policies and launched the Aimhigher associate scheme which will see 5,500 student mentors working in schools."
Liberal Democrat universities spokesman Stephen Williams said: "After 10 years of a Labour government, little progress has been made on widening participation.
"It is the poorest people who are still the least likely to even apply to university.
"The make up of the student body is still poorly understood and ministers must conduct a comprehensive study to gain a full understanding of why certain groups are so under-represented."
"Individual institutions must also be far more transparent about what they are doing to widen participation and the government should be tough on those that aren't doing enough."