Sports coaches and faith leaders who have sexual relationships with 16 and 17-year-olds in their care will be breaking the law under new legislation planned for England and Wales.
The move would put them on par with roles like teachers and social workers.
Children’s charity the NSPCC said it was a “landmark step” for the protection of young people.
It is among a raft of measures included in a bill which is due to be introduced in Parliament later.
Other provisions in the Police, Crime, Sentencing and Courts Bill include:
The government’s plans follow prolonged calls from campaigners for the so-called Position of Trust laws to be extended to cover other roles that have responsibility over young people.
While the age of consent is 16, it is illegal for those in some professions – such as teachers, social workers and doctors – to have a sexual relationship with 16 or 17-year-olds in their care.
Peter Wanless, chief executive of the National Society for the Prevention of Cruelty to Children (NSPCC), which campaigned for the law change, said it was “delighted” the government had agreed to “close this legal loophole”.
“This landmark step sends a clear message that children and young people can return to the extracurricular activities they love without being at risk of grooming by the very adults they should look to for support and guidance,” he added.
The new bill, with its long list of proposals, is being described as a justice overhaul aimed at giving better protection to the public and more backing to the police.
Justice Secretary Robert Buckland said the bill was delivering on the government’s promise to “crack down on crime and build safer communities”.
He said the bill would give the “police and courts the powers they need to keep our streets safe, while providing greater opportunities for offenders to turn their lives around and better contribute to society”.
The government is also investing “hundreds of millions to deliver speedier justice and boost support for victims”, he added.
Home Secretary Priti Patel said the bill would help “stop violent criminals in their tracks, putting the thugs who assault officers behind bars for longer and strengthening the support officers and their families receive”.
However, some campaigners have criticised the proposals.
Responding to the plans for longer sentences, Peter Dawson, director of the Prison Reform Trust, said: “There is not a shred of evidence to show that this runaway inflation in punishment reduces crime.”