The number of students from Wales studying at some of the UK's top universities has dropped by almost 10% in three years, figures have shown.
A total of 6,260 joined Russell Group institutions from Birmingham to York in 2015/2016, down from 6,900 in 2012/13.
Wider figures show a decrease in those going to university generally but the Russell Group has bucked this trend.
The Welsh Government said it wanted to raise aspirations and achievement among students to increase their potential.
The Russell Group is a collection of 24 higher education institutions - also including Oxford, Cambridge and Cardiff - which specialise in research and are widely regarded as being among the best in the country.
The group said it was working with the Welsh Government's Seren Network scheme, which aims to link "bright Welsh sixth-form students with the UK's leading universities and improve their chances of making a successful application".
Education consultant Robin Hughes, a former director of the Association of School and College Leaders (ASCL) union in Wales, said there could be several reasons for the drop in Welsh students going to universities at the upper end of the league tables.
"We have to consider where they're getting their encouragement and information from, what's the basis for their decisions - there's a lot to do in terms of career discussions," he said.
"It certainly would be a shame if we have students who are able enough, who might be missing out on the advantages of studying at a Russell Group university, in terms of career benefits, quality and so forth."
Overall, the number of Welsh students starting courses across the UK at all universities has dropped 10% between 2012/13 and 2015/16.
There has also been a 5% drop in applications to universities from students living in Wales this year.
At the same time, Russell Group institutions have continued to attract more UK students, with entry figures rising 8% from 103,225 in 2012/13 to 111,555 by 2015/16, according to data from the Higher Education Statistics Agency.
"There's nothing to lose"
In 2015, the Seren Network was established by the Welsh Government, to increase the number of pupils from Wales applying to the best universities.
Over 2,000 pupils are now part of the network.
One pupil who benefited this year was Megan Howells, 18, from Coleg y Cymoedd, Rhondda Cynon Taff, who was accepted to study law at Oxford after achieving two A* and two As at A-Level.
"When I started Year 12 I was thinking about places like Bristol as I thought Oxford and Cambridge were out of reach and I didn't think I would be good enough to get in," she said.
"But, over the course of the year, I felt more and more confident, and when I received three As and a B in my AS exams I began to believe that I could aim for Oxbridge."
She added: "My advice to any Welsh students thinking of applying to a top university is to go for it.
"Even if they think they're not good enough or they won't get in, there's nothing to lose, and you never know until you try."
Conservative education spokesman Darren Millar called for a schools curriculum "which helps students achieve their potential and nurtures our highest achievers, so that they can go on to compete with the very best at our elite universities".
"If we allow ourselves to fall behind in this respect then it'll have serious implications for our economy later down the line," he said.
A Welsh Government spokesman pointed to a recent survey which suggested that 95% of Seren's participants had applied or were expecting to apply to Russell Group universities.
"Raising the aspirations and achievement levels of Welsh pupils so that they may realise their academic potential is a continuous priority for the Welsh Government, and the Seren Network plays a vital role in fulfilling this aspiration," he said.
Sarah Stevens, head of policy for the Russell Group, said: "Russell Group universities are committed to attracting students from every part of the UK who have the potential to succeed, regardless of where they live or their family background.
"A number of our members are actively engaging in the Welsh Government's Seren Network scheme, which aims to link bright Welsh sixth-form students with the UK's leading universities and improve their chances of making a successful application."
Plaid Cymru AM Sian Gwenllian said Welsh ministers should ensure higher education was "properly resourced so that more institutions here in Wales can achieve Russell Group membership".