"The main focus of this city would be the establishment of a financial hub for Australasia," he said.
As well as the mega-city, this "international zone" would need an international airport built to serve it. And an international sea port would be required but this could be built based on the existing port facilities at Wanganui.
"This economic zone would be something more in line as to what Hong Kong was and became for the British. The difference is this zone is for China," Mr Churton said.
He acknowledged the plan "is quite a complex project" but the benefits to New Zealand would be vast. He said it could create up to half a million jobs, the city would cost at least $250 billion to build and was a project that would carry New Zealand for the next 30 years.
Mr Churton visited China in June and said it was obvious that country was looking to open up investments in Australasia.
"China is aiming to be No1 in the world. As a country we need to consider such a project as this."
He has written to Nathan Guy, Minister of Primary Industries, outlining his grand plan and Mr Guy's office said the letter had been "placed before the Minister for his information".
Mr Churton said the economic zone would attract tourists from China, and become a business and distribution hub for China.
"It would also help relieve the pressure on the Auckland housing market. The zone would also provide a place for further processing of New Zealand products such as wool, logs and milk.
"And it would also mean we could concentrate more Chinese investment into that zone rather than around the rest of the country," he said.
Farms cover much of the area he has suggested for the zone but he said Government could purchase those by offering "prices too good to refuse".
"Not all the land would be needed straight away so many of the farms could remain in production until the land was needed," he said.
This is not the first time Mr Churton has promoted audacious plans.
In 2002 he launched Port of Wanganui Ltd, hoping to pick up the lease of the port operation at Castlecliff but dropped that ambition about six years later.
In 2010 he was back, suggesting there is a future for the waterfront. In his view the port offered three "viable" options - as a naval base, a log export port or as a ferry terminal. He also offered the Wanganui District Council his services as a consultant targeting future port plans.