People who travel overseas to have sex with children will face a "strike" towards life imprisonment under new proposals that widen the net of the three strikes bill.

The Sentencing and Parole Reform Bill - under which criminals at strike three would get a maximum sentence without parole for any of 40 qualifying offences - was yesterday reported back from select committee amid fierce opposition from Labour.

The committee recommended the bill - which has had five new offences added - be passed, but rejected inclusion of burglary and manufacturing methamphetamine charges as property and drug crimes did not target recidivist violent offenders.

The new offences include having sex with children outside New Zealand; infecting with disease; poisoning with intent to cause grievous bodily harm; counselling or attempting to procure murder; and conspiracy to commit murder.

The bill has also reduced the sentence for a manslaughter conviction at strike three from life without parole under the earlier version of the bill to a minimum 20 years in prison.

If the sentence is found to be manifestly unjust, the bill imposes a sentence of at least 10 years compared with the earlier version, which allowed a judge complete discretion. The change was made to recognise the "wide range of conduct" that can constitute manslaughter, the report says.

A murder conviction would still carry a life sentence without parole at strike two and three, but if proven manifestly unjust, the minimum non-parole period would be 10 years at strike two and and 20 years at strike three.

Auckland University law lecturer Richard Ekins said the manslaughter provisions were a step backwards, citing the case of a person sentenced to 300 hours' community service after being found guilty of manslaughter for not having properly maintained a helicopter.

He predicted the bill would lead to an increase in claims of manifest injustice.

"If someone kills someone in a bar fight [at strike three], judges will be very reluctant to give him life without parole when they can't do the same for a first strike who has tortured, raped and murdered a child."

"They are not going to wear that inconsistency very easily."

Act MP David Garrett, who drafted the original bill, said although it was weaker than the original, it was still an improvement.

"I am pleased. What we are going to have is a huge advance on what we have now, where people can commit dozens of offences and still be sent to jail for three, four, five years. That will be a thing of the past, and that can only be good."

But a Labour report was scathing in its criticisms, saying the bill would have a questionable impact on real crime - according to advice from the Justice Ministry and Corrections.

With no incentive for guilty pleas on a strike three charge, more trials and appeals would put added stress on victims and see court costs soar.

It also criticised the National-Act majority of the committee for refusing Labour a minority report on the interim report and for stopping Justice Ministry officials from advising the committee.

The bill will now be reported back to the House for its second reading.

* Sexual conduct with children and young people outside New Zealand.
* Counselling or attempting to procure murder.
* Conspiracy to murder.
* Poisoning with intent to cause grievous bodily harm.
* Infecting with disease.

- Correction: The story incorrectly states that a third conviction for any of 40 qualifying offences would mean life imprisonment without parole. Under the bill, a third conviction for a strike offence would mean the maximum sentence for that offence without parole, unless it is manifestly unjust. The error was inserted during the editing process.