But if they commit other strike offences between their arrest and sentencing, they do not receive a warning for it.
The Sensible Sentencing Trust has asked Ms Collins to consider amending the law to include "provisional warnings" to ensure offenders are properly subjected to the escalating punishments.
A provisional warning could be given to a person who commits a second or subsequent strike offence while on bail for an initial strike offence.
If the charge does not result in a conviction, the provisional warning would be wiped.
If they were convicted, the provisional warning would be upgraded to an official strike warning and each crime they committed would be recognised.
"We are deeply concerned that the current law allows some of the worst offenders - those who commit subsequent strike offences while on bail - to avoid the next stage of the three strike regime," said trust spokeswoman Ruth Money.
"A similar strike crime committed after the offender has pleaded guilty or been found guilty at trial will not avoid the three strike regime.
"This current law effectively rewards serious violent offenders for offending while on bail by allowing lighter sentences for strike offences committed while on bail facing a similarly serious, or even more serious, charge."
Ms Money said the presumption of innocence until proven guilty was an important tenet of the justice system.
But the reliance on a conviction for the strike to be recorded allowed further serious offending to take place by an accused released on bail - who would avoid the next stage of the three strikes legislation.
Ms Collins said she was not convinced the loophole existed.
"I do not agree that it can be described as a 'loophole'. The 'three strikes' regime included in the Sentencing and Parole Reform Act 2010 is quite clear that specific consequences follow after an offender has been convicted of a qualifying offence and has been given a warning, and then goes on to commit another qualifying offence," she told the Herald yesterday.
"The warning is part of the penalty imposed on conviction. It would not be consistent with the philosophy of the act if offenders were given a warning about subsequent offending before their guilt or otherwise on the original charges had been determined."
Ms Collins said she supported the approach that only offences committed after an offender has been convicted and warned should be covered by the three-strikes law.
"I note that there is a draft members bill, the Bail [Serious Violent Offences Warning] Amendment Bill, that proposes to amend the Sentencing and Parole Reform Act 2010, so ultimately any changes would be up to Parliament to make. No reviews of the three-strikes legislation were planned over the next year.
"However, I am confident the legislation is an effective deterrent to criminal offending and that the system is working as intended."
Ms Money said the trust believed its proposed change was relevant to the Bail Amendment Bill, which was under review.
"It should not be reliant on a member's bill being drawn from the ballot for the issue to be addressed."
Three strikes
Q: What is the three-strikes law?
Passed in 2010, it sets up an an escalating consequences system for serious violent and sexual offenders. After the first conviction for a qualifying offence, the criminal is given a normal sentence and a strike one warning. If they are convicted for a second qualifying offence they receive a sentence without parole. For a third strike offence conviction, they are given the maximum sentence for that offence, without parole.
Q: What is the "loophole"?
Strike offences committed by people on bail for serious offending are not recognised under the system. A first strike warning can be given to a person only upon conviction, and subsequent strikes for offending after that. No strikes can be given for serious offending that occurs between the first charge being laid and the conviction being entered.
What do victim advocates want?
They want provisional warnings given to people who commit strike offences while on bail for an initial strike offence. If they are convicted of the offending, the provisional warnings would be made official.
How many people have been given strike warnings since 2010?
By August, 1892 people had been given first strike warnings after being convicted for qualifying offending such as sexual or violent crime. Eleven offenders have been given a second strike.
