The company behind an iconic Kiwi Easter egg

A change in shape for Cadbury's marshmallow Easter eggs left a sour taste in the mouths of many New Zealanders.

It also increased demand for locally-made products, including one factory in Oamaru still making Easter eggs by half.

Easter's still two months away, but production lines at Rainbow Confectionary have been running since before Christmas.

An extra 40 staff are working flat out, piecing together Easter eggs the old fashioned way.

Brent Baillie, Rainbow Confectionery general manager, says they are making the eggs the traditional way it has always been done.

"We're doing it the way kiwis expect it to be done."

To make the Easter treat the marshmallow egg halves are covered in chocolate.

One side is heated before the halves are pushed together by hand to form a whole egg.

Rainbow started production back in November last year, winding up today after turning out 9 million marshmallow eggs.

Rival Cadbury used to make its eggs the same way, before Mondelez closed the Dunedin factory last year, costing over 300 jobs.

New Zealanders are the biggest consumers of marshmallow eggs, many disappointed with the company's new Australian-made versions.

Cadbury says the switch to a flat-bottomed shape is due to "upgraded equipment".

"Other overseas markets aren't necessarily interested in them. That's why it might be an inconvenience to make these offshore, and bring them into New Zealand.

"But it's not an inconvenience for us to make what Kiwis know and love," Mr Baillie says.

The Oamaru company produces over 3000 tonnes of confectionery every year.. including Easter eggs for most of the country's supermarkets and retailers.

Orders are up this year, with a consumer backlash against the altered imported ones.

"When the consumer goes to the supermarket and goes to buy a product. I hope they speak with their wallets. I hope they support New Zealand-made manufacturers," Mr Baillie says.

Keeping it Kiwi and ensuring the traditional shape of a New Zealand classic keeps rolling on.