Dozens of top Australian executives are flying into Wellington for a two day briefing on investing in the rock star economy.

More than 70 Australasian managers of global companies and 30 bosses of Kiwi companies are in Wellington on Tuesday and Wednesday for the New Zealand Foreign Investor Dialogue.

The Government is laying out the red carpet for the two-day forum, from which the media is barred. Ten Cabinet ministers including Prime Minister John Key and Finance Minister Bill English will speak on Tuesday and Wednesday along with Opposition leader Andrew Little and his finance spokesman Grant Robertson, and Reserve Bank governor Graeme Wheeler.

NZ First leader Winston Peters was invited to speak but declined due to a scheduling clash.

The event is held every three years, but organisers, the International CEO Forum and the Hugo Group, say registration is significantly stronger than recent forums.

New Zealand was dubbed the "rock star economy" by HSBC economists in 2014, and interest in the country appears to be unusually strong, as Australia's economy wanes as the mining boom ends.

"If you're based in Australia, New Zealand looks pretty interesting at the moment," Hugo Group director Pattrick Smellie said.

"Our growth story is more robust, and it's just a sense that they should take a greater interest than they normally would."

Organisers of the event have been firm that the media cannot attend, in a bid to have ministers give "free and frank" answers to potential investors.

"It's not that anybody expects anything unusual or secretive, it's more that it's an environment where everybody can speak plainly to one another without having to worry about whether anything they say can be misinterpreted or picked up on," Smellie said.

Economists say although New Zealand faces challenges, its growth in 2014 was among the strongest of any developed economy, and is substantially stronger than in Australia.

Although New Zealand's Budget this month is expected to show a seventh straight deficit of around $500 million, Australia's Crown accounts are expected to show a deficit of more than $40 billion according to forecasts, pushing the Kiwi dollar close to parity with Australia for the first time in decades.

"We're a bit of an aberration in that we have modest to strong growth, we're creating employment, the outlook is still reasonable and we've done that without creating it with excessive monetary stimulus [low interest rates] or excessive fiscal stimulus [government spending]," BNZ head of research Stephen Toplis said. This meant that an increase in interest from Australia would not be a surprise.

"We're in an environment where the relative economic performance is superior and people are questioning why that's the case."