Children found guilty of robbery, dealing drugs to other children or violent disorder will no longer have to disclose their criminal records to prospective employers under sweeping government proposals to change the youth justice system.

People in England and Wales will not have to share records of crimes committed when they were under 18 for the rest of their lives under the proposals, which ministers say will boost youth employment and make life fairer for people from disadvantaged backgrounds in particular.

The proposals, which are being consulted on, are part of a wider set of changes that aim to sharply reduce the number of children in custody and increase support for those who are convicted of crimes.

Jake Richards, a justice minister, told the Guardian: "Where it's safe, we believe as a government, people should have second chances – second chances to make something of themselves, to contribute to work and to turn their back on crime.

"The system at the moment doesn't discern for offences committed when you were a child than those that you committed as an adult."

Richards is proposing to reduce the number of offences that would require lifelong disclosure on standard and enhanced DBS checks by the person who committed them. If the plans become law, people convicted of violent disorder, supplying drugs to a child, robbery, affray and actual bodily harm when under 18 would no longer automatically have to disclose those offences for the rest of their lives.

If they are convicted of one of those offences but do not get a custodial sentence, they will have to disclose them only for five and a half years. If they get a sentence of two years or less, they would have to disclose it for 11 years.

Anyone given a longer custodial sentence would still have a lifetime obligation to tell prospective employers.

If someone is convicted of a crime which results in a fine, they will no longer have to disclose it, rather than for the next six months as the law currently stipulates.

Jobs in the UK that require a standard or enhanced DBS check include teaching and early years working, social work, healthcare and transport jobs including taxi driving.

Other changes include ending the automatic disclosure of any out of court resolution and ending a rule which lengthens how long it takes for a conviction to become spent if the person is convicted of a second crime during their rehabilitation period.

Campaigners have welcomed the proposed changes, saying they will boost youth employment. Companies say criminal convictions are the second biggest barrier to employing people from disadvantaged backgrounds.