Protesters with hula-hoops have greeted pig farmers attending their annual conference in Wellington today.

Activists say the hula-hooping highlights how little space pigs have in fattening pens, where the animals are raised for pork meat.

Animal rights group Safe said the protest follows the release of new undercover footage taken by activists of pigs in crowded conditions, including "an underweight piglet with presumed neurological issues struggling to walk and falling over, a pig with a prolapse showing great discomfort, and many pigs living in wet and filthy conditions".

The protest was outside the NZ Pork conference at the Rydges Hotel in Wellington.