Prime Minister John Key yesterday spoke of his vision of a seamless transtasman economy with broccoli diplomacy at the giant x-ray facility of the Southern Hemisphere's largest scientific instrument.

In a practical illustration of the potential for New Zealand and Australia to gain the "grunt" to jointly take on the rest of the world, Mr Key visited the Australian Syncrotron in Melbourne to look at cancer-beating transtasman vegetable research.

He emphasised it further with a call on transtasman construction giant Fulton Hogan's Dandenong Creek wetland project, designed to leech pollution from stormwater.

Today he will meet Australian counterpart Kevin Rudd in Canberra to discuss further measures to bind the two countries into a single economic market, including an expected announcement on plans to remove barriers on flights across the Tasman.

Mr Key also wants to slash red tape on trade, investment and business, and to shape the two economies into a force that can team up to position themselves for the world after the global economic crisis.

"We need to develop an environment for business that releases our countries' productive potential and, importantly, increase the growth, productivity and profitability of our tradeables sector - our companies that are in competition with the rest of the world,' he told the Committee for the Economic development of Australia.

Mr Key said he wanted to achieve a seamless business environment in which a company in Melbourne could do business in Auckland as easily as it could in Sydney.

Mr Key said Wellington and Canberra could make a real difference by developing smart regulation, driving productivity gains, and capitalising on their joint capacity for international influence.

"It helps us insert into global supply networks by giving us the combined grunt to plug us both into regional and global networks, including through our expanding network of free trade agreements," Mr Key said.

Australia and New Zealand were working together as "powerful allies" on trade policy, with plans for a new transpacific partnership stretching from the Americas to Asia.

"A robust and progressive single market is a cornerstone of our current and future relationship," Mr Key said.