Prime Minister John Key visits the Chatham Islands on Thursday at a time when more and more young families are leaving for good.

Faced with high power and grocery bills, and expensive housing, about 40 people left recently for West Australia's mines.

Part of Wellington's Rongotai electorate, islanders live 750km from the rest of New Zealand, and say investment in infrastructure, such as an upgraded wharf, extended runway, a hydro-electricity scheme, and a meatworks, are vital to boosting fishing, agriculture and tourism.

The Chathams' 11 islands add thousands of kilometres to New Zealand's exclusive economic zone, and their fishing and agriculture contributes around $200 million a year to the national economy.

Key will be accompanied by Treaty Negotiations Minister Chris Finlayson, who has special responsibility for the islands, and who says plans for an upgraded wharf are progressing. He said the islands made a significant contribution to New Zealand.

"These guys are not bludgers with their hands out. These people are really enterprising. . . they continue to punch above their weight for New Zealand."

Mayor Alfred Preece met Key in Rarotonga this month. "I happened to run into him and he was keen to come across. He's looking forward to a feed of crayfish."

Preece's focus is getting work under way on port facilities at Waitangi and Pitt Island. The wharf was built 20 years ago but "concrete cancer" means it's crumbling.

"Key is pragmatic so the community will enjoy having a chat about how we are going to implement the programme."

Having no breakwater in Waitangi Bay means the ships that carry in vital supplies can't berth in stormy weather. "We lose about 60 days a year and those costs get passed on and make shipping expensive."

An upgrade will cost between $25-30 million for Waitangi, and another $3-6m for Pitt Island, home to about 50 people. But the work is essential to attract development, particularly a company that hopes to mine phosphate in the Chatham Rise.

Cray fisherman Jeff Clarke waved his 13-year-old son off to school in Hastings this year because, although there are three primary schools with a combined role of 65, there's no secondary school.

He knows teenagers rarely return and says huge power bills drive both businesses and residents away.

"The cost of processing fish on the island is astronomic. Once you have cheaper power you have a flow-on effect."

Clarke holds a lifetime quota he can pass on to his son for nine tonnes of crayfish and 24 tonnes of blue cod. "If you are a quota owner you can go to a company and barter your own destiny. But the major owners are offshore."

Chatham Islands Hotel owner and dad-of-three Val Croon is kept busy running a hotel, the island's only pub, guided tours and fishing trips. He says tourism is the island's fastest growing industry seeing about 1500 visitors a year.

"We are probably running at capacity, so we need those infrastructural things to happen. It's very hard for an island to grow when people don't want to start up a business because of the power and freight being expensive."

Croon's grandmother was born on the Chathams but left for Auckland. The family returned when he was two, and he lives there with Russian wife Natasha.

"It's a great place to bring up children. Open spaces, nice and safe. We just need more industries."

Dough ‘n' Go owner Kath Morrison has waited through five days of bad weather for a ship to dock to restock her local shop.

"It affects everyone because the farmers have their stock ready to go out and there's the fuel too. We need that for our power, and the fire brigade and ambulance."

Morrison came to the island to teach 28 years ago but today says businesses are declining alongside the population.

It's hard for young families, and a lot have left, most for Australia. The doctor left in April. "We're on a series of relieving doctors. Which is very hard on people who have long-term health problems or pregnant women."

- © Fairfax NZ News