Leitch said that should have "changed the political landscape" in New Zealand but instead it only amounted to two seats under the first-past-the-post system.
It was used later used as an argument for the introduction of proportional voting, and Social Credit helped campaign for the MMP system we have now.
Leitch said the time was right for Social Credit's central philosophy, which remains the same.
It argues instead of Government borrowing money from the private banks, with interest attracted, it should create money for Government assets through the Reserve Bank.
"It is still debt but it's non-repayable debt... and it doesn't need to have interest paid on it. It's actually the reserve bank taking an investment in the country," he said.
"It's newly created funds but it's available for the Government to spend on infrastructure projects and housing and so on."
Leitch said there was little difference in money created by private banks or central banks except that it would save on interest payments and help reduce things like fuel taxes which the party wants removed.
"They can't just simply spend whatever they like because if they're going to do that they're going to create significant inflation.
"Provided the Government doesn't create a greater amount than they would've created through private banks then inflation is not a problem."
Leitch said such economic policy was used in Europe.
"I think you can talk about things like $5 billion in taxpayers' money [currently spent on interest] that should be going into hospitals so you can get proper health care - those kind of messages tend to distil it down to things people can understand."
