Unemployed over-50s will be offered "career reviews" and help using computers as part of plans to get more people in that age group into work.
The trial will also include seven "older worker champions" across the UK.
An estimated 1.2 million over-50s are unemployed and "willing to work" - and ministers said if they all found jobs it would "add £50bn to the economy".
Employment Minister Esther McVey told the BBC it was "wrong" so many skilled people were "locked out" of work.
Long-term unemployment in the wider population fell 16% in the past year - but joblessness among the over 50s fell by 3.5%.
The trial, to be launched in April, will include training in CV and interview skills, the internet and social media, as well as "career reviews" with an expert to identify skills from previous work and any training needs.
"Champions" will be appointed in seven areas of the UK, at a cost to the government of £250,000. These Job Centre staff will focus on "going out to smaller and medium-sized businesses to ensure they recognise the benefits of hiring older workers".
Ms McVey said it was about "challenging outdated stereotypes".
"The plight of unemployed older workers has gone under the radar for too long. There's something fundamentally wrong with so many skilled and experienced people finding themselves locked out of the workplace simply because of their age," she told BBC Radio 5 live.
She pointed to "record numbers" of people getting into work since 2010, adding that in the past year more than 250,000 people over 50 had found jobs.
Ms McVey said it was not a question of older workers taking the place of younger employees.
"More jobs are being created in the UK than anywhere else in Europe... We've just got to make sure that everybody is a part of that growth."
Out of work
- A quarter of women and one in six men who reach state pension age have not worked since they were 55
- Almost half (47%) of all unemployed people between 50 and 64 have been out of work for a year or more, compared with 33% for those aged 18-24
- There are "positive effects" on younger staff when more people aged 55-64 are employed, research has suggested
- Those aged 50-64 have an average job tenure of 13 years, compared with seven years for those aged 25-49
Source: Department for Work and Pensions
The Equality Act 2010 makes it unlawful to discriminate against employees, job seekers and trainees because of their age.
Ms McVey ruled out further legislation, saying: "Where there needs to be laws, they have been brought in, this is about working with businesses and encouraging people that this is the right thing to do."
Caroline Abrahams, of charity Age UK, told 5 live: "The last thing people want to be doing is having to dip into their savings in their late 50s. It's a really bad thing if you lose your job in your 50s and we know that if you do it's awfully difficult to get another one."
The estimate of the number of unemployed over-50s "willing to work if the right opportunity arose" comes from a report published in October by the International Longevity Centre think tank.
The report stated: "Efforts must be taken to ensure that these individuals do not end up permanently inactive."
The latest figures show unemployment fell by 63,000 to 1.96 million in the three months to the end of October - the first time it has fallen to below two million for six years.