Winston Peters says New Zealand First wants to limit foreign ownership of residential property, and ban foreign boats and crews from fishing New Zealand waters.
Mr Peters told TV3's The Nation he would not "stand around while somebody from off shore with 77 homes, and has now become a major landlord in Auckland and filtering in, and gauging money out of our economy".
Asked whether that would drive property prices down by reducing demand, he said some demand was of no use to New Zealand.
"I live in an area where the house prices have gone up 114 per cent. Now you can't save that fast and I can't, and there's not many people watching this programme that can save that fast. So where does a young family fit into this country? They haven't got a hope in this context."
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Mr Peters said New Zealand wanted to see the "New Zealandisation" of the fishing industry.
"So our fish is caught by New Zealand boats and New Zealand fishermen and is added value that is packaged here and sold here and sold offshore. I don't see how we can get any advantage from foreign crews sending the raw product to China, and have it tinned back to our supermarkets."
Foreign crews would be given an "exit strategy" and compensated for their losses.
The fishing resource needed to be part of the country's employment and wealth creation, he said.
"For goodness sake, the Maori people have got a sizeable chunk, as you know, of the Maori fishing industry and who's catching Maori entitlement or Maori quota fish? Foreigners are."
A key priority for the party would be the buy-back of state assets, with Mr Peters saying "if either side prefers to sell out New Zealand's long term heritage, then they can line up and find their own support".
New Zealand First would not work with United Future or the Maori Party after the election, he said.