ACT thinks more people should be in jail.

The party's law and order policy would invest $1 billion into 500 more prison beds, and toughen sentences for offending against vulnerable workers.

Leader David Seymour says the Government has tried letting criminals out of prison.

He says a Ministry of Justice survey shows the result.

"Victimisations are up by about 30 percent in 5 years, but the human price of that is that people feel it's not safe to run a dairy- and for some people, it's been absolutely tragic."

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