If NZ meat is sold cheaper in the countries that it is exported to, why aren't meat producers preferring to sell their meat in NZ...?

Possibly VOLUME has much to do with it. And it is a part of TRADE.  That way NZ gets new money into its country...to help its economy.  All country economies work on trade.(unless they have been excluded from that market such as N.Korea(which still sneaks some trade deals with China) to keep afloat.

I purchase retailed products that include 

goods from Australia and New Zealand.

I prefer the crisp taste of NZ apples but

it is a seasonal item.  Can meat is of a

quality above some USA product but I recommend can tuna fish shipped out of 

Pago Pago.  Close enough ?  NZ could

cultivate beef grow amid Oceania to

lower transport cost.  Such as French 

New Caledonia.  Is that too European?      

You've confused retail with wholesale.

Producers don't get the retail price, which is what you're comparing.

It is not simple thing . Lamb does not grow over night . If you have too many and no place to sell them when they are ready to be sold ,you either have to sell it cheaper or continue loosing money on feeding it or storing it in freezers. And it goes further than that of course .

It's because NZ produces far more food than it consumes. They have to dump it somewhere.

I'm not sure where you get the idea that it is cheaper in other countries. I'm in the US and buy New Zealand lamb and it's generally more expensive than American lamb.

There is also a limited market in New Zealand. It's about 1/4 the size (population wise) of just the greater Los Angeles area!