New measures to spare alleged rape victims from facing live cross-examination in court will be rolled out as part of changes being made by the justice secretary.

Liz Truss announced that from September victims in England and Wales would be able to provide evidence in prerecorded cross-examinations to be played to the jury once a trial begins.

The rule applying to all adult sexual offences is being introduced following the success of pilot schemes using prerecorded evidence in cases of child sexual abuse.

It was found that defendants, when confronted with the strength of the evidence against them before the trial, were more likely to enter an early guilty plea, reducing the trauma for victims, speeding up the justice process and saving money.

The move comes amid changes that include a crackdown on paedophiles grooming children on social media with a new offence of “sexual communication with a child” to be brought in. It will mean those convicted face a jail sentence of up to two years and an automatic listing on the sex offender register.

Truss said the changes to rape trials would prevent victims facing the trauma of confronting their attackers without reducing the right to a fair trial.

She told the Sunday Times: “There is more we can do to help alleged victims in these cases give the best possible evidence they can give in an environment that is much more suitable than open court. We’ve been trialling this for children in cases of sex abuses.”

She added: “What this has led to is a much higher level of early guilty pleas. That has a huge amount of benefit. It resolves the case much earlier for the victim. It reduces the level of trauma for the victim. I want to see that being the standard offer in those cases and that will give more victims the confidence to come forward.”

Rape prosecutions are at record levels and the court system is struggling to cope with the high caseloads.

Domestic abuse, rape, sexual offences and child sex abuse account for 19% of the Crown Prosecution Service’s total caseload – more than double the figure six years ago.

The volume of rape referrals to the CPS from the police rose to 6,855 in 2015-16 – up 11% on the previous year. Of those referred, 3,910 resulted in charges and 1,300 in convictions. However, campaigners claim only 6% of all reported cases result in a conviction for the perpetrator.

The new regulations will aim to improve the conviction rate with victims and vulnerable witnesses able to give evidence “in a room in court where it’s much less intimidating, where there are ground rules set by the judge”, said Truss.

She said the changes would mean judges can limit the length of cross-examination to avoid victims having to testify for days on end and would also allow them to cut out any inappropriate cross-examination of a victim’s sexual history before it could be aired before a jury.

Prerecorded evidence is already being launched nationwide for child sexual abuse cases.

The victims’ commissioner, Lady Newlove, welcomed the news that the government is to strengthen the support available to victims in the courtroom. “Prerecorded cross-examination allows vulnerable victims and witnesses to give evidence in a safe environment and I hope these long-awaited measures will provide the protection and reassurance they need to seek justice,” she said.

However, some questioned whether the new measures would place the defendant in rape trials at an unfair disadvantage.

James Conte, who founded the website Accused.me.uk, a support group for victims of false allegations, said: “Whilst we would welcome measures that would increase the rape convictions of people who really have committed rape, if you are wholly innocent of someone trying to frame you, you will not welcome these changes because they will increase your chances of being wrongfully convicted.”

But Lisa Avalos, a professor of law at the University of Arkansas who has carried out comparative work on rape prosecutions between Britain and the US, said false allegations of rape make up just 2-3% of all rape allegations according to a study commissioned by the Home Office.

Avalos, an expert on gender-based violence, said: “The overwhelming problem here is rape, it is not false allegations of rape. Studies have shown the majority of false allegations of rape involve unnamed perpetrators so the concerns some organisations have about reputational damage to identifiable individuals are substantially overstated.”

She added: “Concern with false allegation masks another problem, namely that disbelieved rape victims have been wrongly accused of false reporting. Approaching rape victims with scepticism enables rape and discourages victims from coming forward.”

Avalos said that if rape cases were properly investigated in the first place, false allegations would never come to court.

She said: “There are massive failures to properly investigate rapes with police officers only referring between 10% and 30% of all reported cases to prosecutors. There are some international organisations that are putting out excellent rape investigation guidelines but such guidance is yet to be embraced by the UK.”