The parents of Sarah Payne, James Bulger and Damilola Taylor are taking part in a debate on the sentencing of killers.
Sara Payne has campaigned for harsher sentences
They are joining more than 100 delegates to discuss proposed changes to the Criminal Justice Bill at a conference for victims of homicide.
Home Office Minister Lord Falconer is due to speak about the plans, which include imposing full life sentences for paedophiles who abduct and kill.
It comes after the case of paedophile Michael Wheeler, 36, whose three-year jail sentenced for 11 sex offences against two girls aged 13, was criticised on Friday.
The conference, being held at South Shields, south Tyneside, marks the first time many of the families of the murdered children have met.
The North of England Victims Association, which is organising the conference, has long campaigned for tougher sentencing.
The families aren't being considered... they are the ones that are left behind to clean up the mess
Sara Payne, the mother of murdered schoolgirl Sarah, said victims wanted "anyone that murders anybody to be put away in prison for life".
"None of this 15, 20, 25 years - life should mean life," she said.
Her eight-year-old daughter was killed by Roy Whiting, a convicted sex offender, in July 2000. He was jailed for life in December 2001.
When Home Secretary David Blunkett announced the proposed new measures contained in the bill last month, he said they would mean punishments for murderers would better fit their crimes.
Under the proposals, Parliament will be able to lay down guiding principles for judges in England and Wales to determine how long an offender should spend in prison before being considered for release on licence.
These include the principle that anyone who abducts and murders a child should never be released from prison.
Whole-life terms will also be imposed for terrorist murder or multiple murders which are premeditated, sexual or sadistic.
Speaking to BBC News, Lord Falconer said the conference was to emphasise how "the voice of the victim has got to be heard much more in the criminal justice system".
Commenting on the Michael Wheeler case, he said: "The sentence was too low, but not I suspect because of what the judge did but because the maximum sentence available was not high enough."
He said the Sexual Offences Bill going through court would increase the maximum sentence for having sex with a girl of 13 and over from two years to 14 years.
But he denied the government had "lagged behind" in making the changes and said: "It is not something you can do overnight, it required a substantial amount of consultation and we brought forward a substantial series of proposals for reform."
'Consideration for families'
The plans have come in for criticism from some members of the judiciary and civil liberties campaigners, who have questioned the right of a politician to take decisions in private over sentencing, leaving prisoners little right of appeal.
But they were welcomed by delegates gathering for Saturday's conference, who are pushing for better rights for the relatives of murder victims.
"The families aren't being considered at all and they should be considered because they are the ones that are left behind to clean up the mess," Mrs Payne told BBC News.
She added that although the proposals were welcome, "we continue to fight the justice system because it's all very well to say these things but putting them into action - that's what we need to do."
June Richardson, the mother of Martin Brown who was murdered by 11-year-old Mary Bell in 1968, said the government had "a long way to go" to satisfy victims' families.
She said there should be a government minister to look after the needs of victims' families.
"There should be someone that homicide victims should go and talk to on a one-to-one basis and find out what the laws are and what they mean," she said.
"The victims need looking after a lot more than they've been looked after. Hopefully this is another little step today at the conference.
"It's a good thing because people get to meet other victims and help us all to get on with their lives."