Kiwi businesses want help to get to the start of supply chains to ensure there's no slavery or exploitation.

An open letter's being handed to Government today asking for an inquiry into whether we need a modern slavery act.

It's signed by 85 New Zealand companies including the Warehouse Group.

Chief product officer Tania Benyon told Mike Hosking they're able to look into the factories they have a direct relationship with, but it needs to go further than that.

"That's why legislation is important to help businesses get further and further down the supply chain to understand what's happening."

Benyon told Mike Hosking there's similar legislation in other countries and people will back it here.

She says the public are starting to care about where goods are purchased and that it's done in an ethical and safe way.

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