Just last month the country’s High Court rejected protest group Forest and Bird's appeal against an Environment Court decision for the Cypress mine to go ahead.

On its website Save Happy Valley has called for “as many people as possible to join us in Happy Valley, especially during the first weekend of the occupation”

Solid Energy has now set about with detailed planning and preparation work to enable development to start on-site this year. The company will mine five million tonnes of coal over 10 years at Cypress.

The Save Happy Valley coalition said the mine would destroy the habitat of threatened species of the great spotted kiwi and the Powelliphanta “patrickensis” snail.

Solid Energy previously said it would develop a 17-hectare fully fenced, predator-controlled habitat to protect the snail species. The company also said it would relocate as many live snails into the area as possible.

Solid Energy also proposed relocating 10 great spotted kiwi from the mining site and undertaking predator control in a 1000ha area of conservation estate near the mine.