Signatories to the UN migration pact agree in principle to have a unified philosophical approach towards migration into the future.
Despite being non-binding, it's caused consternation around the globe - Australia and the USA have both said they won't sign the agreement, and countries like Italy and Belgium have also pulled out.
The government hasn't formally signed up, but the National Party says if it does, and National's then elected in 2020, it'll pull out.
Professor Paul Spoonley from Massey University joins us to explain a bit more about the background to this agreement, and why there's such controversy around it.