Laszlo Andor said youth unemployment was too high and the Government's Youth Contract, which has been championed by Deputy Prime Minister Nick Clegg, was not doing enough to tackle the problem.
It is the latest attack on the Government from Mr Andor, whose previous criticism of David Cameron's "nasty" looking restrictions on benefits for foreigners, led an angry Prime Minister to lodge a formal complaint.
Figures released last month showed 912,000 young people aged 16-24 were unemployed in November 2013 to January 2014, down 29,000 on the previous quarter and down 81,000 on the previous year.
The unemployment rate for 16-24 year-olds was 19.8%, down 0.7% on the previous quarter and 1.4% lower than the previous year. In Scotland, the youth unemployment rate was the same but the latest figures show it had actually increased by 2.1% year-on-year.
Mr Andor said more needed to be done as he promoted the European Commission's Youth Guarantee scheme, which ensures that all young people under 25 have a "good-quality, concrete offer" of a job, apprenticeship, training or continued education within four months of them leaving formal education or becoming unemployed.
Writing on Twitter he said: "With youth unemployment too high at over 19% UK should implement Youth Guarantee; existing UK YouthContract not sufficient to deliver."
The Youth Contract involves offering firms £2275 for each 18 to 24-year-old they took on who had been unemployed for more than six months.
A Government spokeswoman said: "The UK youth unemployment rate is below France, Italy, Spain and the EU average.
"The number of young people in work here is on the rise and youth unemployment is falling, but there is more we want to do as part of the Government's long-term economic plan to ensure young people have the skills they need for the jobs they want now and into the future.
"Around 200,000 young people so far have benefited from the Youth Contract and our placement schemes, and with a further 100,000 opportunities on offer next year there is a place for any young person who wants one."
Research published last month found that the number of unemployed young people in Scotland could form a line that stretches almost 40 miles.
If the 64,000 16 to 24-year-olds in Scotland who are out of work all stood in line, it would be 38.5 miles long, according to figures from the House of Commons library.
Across the UK, the 734,000 16 to 24-year-olds who are out of work, including those not eligible for benefits, could form a line about 434 miles long, the research also suggested. That is further than the distance from Edinburgh to London.
l Vacancies have continued to increase but a shortage of candidates is emerging, suggesting a "core group" of long-term unemployed unable to find work, according to a new report.
Demand for staff increased last month in private firms as well as the public sector, said the Recruitment and Employment Confederation (REC) and KPMG.
Their survey of 400 recruitment consultancies found that the availability of permanent and temporary staff fell at the sharpest rate for a decade.
Starting salaries for people placed in a permanent job increased last month, said the report.