Justice Minister Paul Goldsmith's bill proposes new offences for assaulting or injuring police, corrections, ambulance and fire officers with intent - a New Zealand First policy.
The new offence of assaulting a first responder with intent to injure would mean up to five years in prison - two years higher than the standard offence - while injuring them with intent would carry a sentence of up to seven years and counts against the three strikes regime which can impose mandatory minimum sentences.
Labour's Justice spokesperson Duncan Webb said attacks against first responders already attracted longer sentences. "So this is doing more of the same."
Webb said harsher sentences were not an effective deterrent - and the three strikes law, for example, failed to reduce offending.
He said the government should focus on recruitment to support first responders.
"We think the better response would be to recruit more Corrections officers and the 500 police officers that haven't turned up yet.
"That's what really makes them safer - to support them in the work that they're doing."
Goldsmith said first responders ran towards danger rather than away from it to help those who needed urgent assistance.
"Assaulting them puts multiple lives at risk, so there must be greater consequences for these heinous acts of violence. Our hardworking police officers, firefighters, paramedics and prison officers deserve better," he said.
The proposed legislation was promised in National's coalition agreement with New Zealand First, and follows a Member's bill by then-NZ First MP Darroch Ball was rejected in 2020 by Labour and National, which said it was poorly drafted.
The announcement follows a suite of sentencing changes that came into effect on Sunday.
