National is blaming the Government's effort to reduce the prison population for a rise in serious crime.
Figures released by the party show since October 2017, when the Labour-NZ First coalition took power, there has been a 26 percent increase in the number of active serious harm cases at district courts across the country. But these figures are at odds with numbers released by the police and Statistics NZ.
Bridges told The AM Show on Monday there have been particular spikes in south Auckland, Christchurch, west Auckland and his own electorate of Tauranga.
"You've got increased gang tensions, you've got meth which is out of control, you've got more shootings. You've got a phenomenon of this Aussie criminal stuff coming over here, I think that is part of it," he explained.
"But I also do think it's the Government going soft on crime. You've got prison numbers coming down."
- Māori over-represented in prisons due to colonisation - report
- Budget 2019: $98 million for Māori-focused prison initiative
The prison population has fallen 7 percent in the past 12 months, a flying start to Corrections Minister Kelvin Davis' plans to bring it down 30 percent over the next 15 years.
"I came into politics to make a difference for our people, our Māori people, and the incarceration rate of our people is something that cannot be tolerated anymore," Davis told Newshub Nation earlier this month, announcing a $98 million "kaupapa Māori" initiative to help prisoners make their current stay behind bars, their last.
National's headline figure - that serious harm is up 25 percent - could be misleading. It measures serious harm offences currently before the courts in April 2019 to October 2017 - but the figures also show spikes in offending in the first few months of 2018, followed by a drop later in the year.
"Numbers of active cases may be affected by seasonal patterns," the document states.
Comparing April 2019 to April 2018 - removing the effect of any seasonal pattern - still shows a jump of about 14 percent however.
"When crime is going up, and serious crime is going up... that does by definition make us less safe," said Bridges.
Official statistics paint a different picture. Overall crime in the 12 months to January was down 1.9 percent, assaults down 1.7 percent, according to the police.
And Statistics NZ data shows the number of convictions in 2018 for homicides, assaults (including sexual), dangerous and negligent acts, abductions, harassment, robbery and extortion were all on a par with 2017.
A spokesperson for Police Minister Stuart Nash said the higher number of cases before the courts could be a result of having more police on the beat, and the police being easier to reach than ever, with the launch of a new phone number for non-emergency cases.
Under the final two years of the previous National-led Government, the prison muster went up 18.5 percent. Bridges says that's fine, if that's what it takes to keep Kiwis safe.
"If you've got a situation where crime is rising and you've got the other thing, which is the prison population is falling, that's no good. Now there's lots of people out there, bleeding hearts, who say 'oh, but look, this is terrible' - I would rather have prisons fuller and streets safer."
Davis said overcrowded prisons make rehabilitation efforts less successful, calling National's policy of building "billion-dollar American-style mega-prisons" a "catastrophe".
Newshub has contacted Justice Minister Andrew Little for comment.