Families of manslaughter and murder victims in England and Wales should be allowed to tell the courts of their grief, ministers say.
Families could speak out after conviction but before sentencing
A government consultation paper will propose bereaved relatives address the judge after the conviction but before the sentencing of a killer.
Families could speak in person or via a lawyer or "victims' advocate".
The Victim Support charity and lawyers expressed doubts about how much effect it would have on sentencing in reality.
The government said the move will be trialled in five courts from April and the results will be closely monitored.
In Scotland a two-year pilot scheme allowing victims or their relatives to submit written statements to judges prior to sentencing is due to end in November.
A Scottish Executive spokesman said it would also "watch with interest any developments relating to victims' advocates in England and Wales to see if they would have advantages for Scotland".
Constitutional affairs minister Harriet Harman is due to launch the consultation for England and Wales on Thursday morning.
She said: "I was very struck by the sense among bereaved relatives that they were completely excluded from the system.
"It seemed to me an incredible paradox that the people for whom the case matters most are silent in court."
She told BBC Breakfast that she was sure judges would "listen very carefully" to victims' relatives.
"And if it means they have a better understanding of the effect of the crime on that whole family, it can only be a good thing."
The government is hoping to pilot victims' advocates in up to five areas.
Ms Harman said the scheme would be closely monitored to "see how it works" and areas examined such as how many relatives choose to use it. The government will also gain the opinions of judges and lawyers.
If considered successful, the move will be "rolled out" to all other courts, she added.
The Support After Murder and Manslaughter (Samm) group described the government's plans as "excellent".
Rose Dixon, of Samm, said: "It's something we and other victim groups have been asking for a very long time."
But the Victim Support charity said the grief of relatives should not be linked to the sentencing process.
"We have got a legal system whereby the state says it is the state's job to assume responsibility for punishment," a Victim Support spokesman said.
Judges already take into account the affect on victims. A victim impact statement - a written statement from relatives taken by police - is presented to the judge before sentencing.
Janet Paraskeva, chief executive of the Law Society, which represents solicitors, questioned whether the latest proposals were necessary.
"We recognise the terrible impact that serious crime has on a victim's family," she said.
"However, we question whether this proposal is appropriate or necessary, particularly as the effect of the crime on the victim's family can already be given in a victim's personal statement.
"It could unduly affect sentencing decisions where victims have no relations to speak on their behalf."
She also questioned how the system would be funded.