"We've fallen slightly short, we need somehow to get it over four," Roberts said.
International spending was easy to forecast compared with spending by Kiwis at home as the industry was more fragmented, with different regions trying to do different things.
But a TIA meeting in Wellington yesterday heard the economic outlook looked positive and this would give New Zealanders confidence to spend, Roberts said.
"In total, we saw a 5 per cent increase.
"So we've made a promising start but there's a long way to go."
There were many more opportunities the industry could exploit, such as increasing New Zealand's air connectivity.
A recent International Air Transport Association forecast projected that air routes to, from and within the Asia-Pacific would carry an extra 1.8 billion annual passengers by 2034.
New Zealand had less than half the number of the 55 international carriers that served Australia and its airport and border agencies needed to do what they could to encourage more to fly here and smoothe the passage of visitors into the country.
"New Zealand needs to ensure it had the infrastructure and tourism products available to get its share of that growth," said Roberts.
Prime Minister John Key said overseas investment in tourism infrastructure was welcome.
"You are seeing quite a lot of international investment focused on the tourism sector," Key said.
"We have a number of high-profile international visitors coming to New Zealand from the G20 and we have plans to take ... them into a range of initiatives their home investors have an interest in investing in."
Key said the Government would push SkyCity on a timetable for building its Auckland hotel and convention centre complex.
Convention centre plans were firm in Wellington, Christchurch and Queenstown.
Business and convention traffic would smoothe out peaks and troughs during the year.
"The challenge is not filling up the place in February, the challenge is filling it up in September."
Key said more labour flexibility, Resource Management Act reform and the introduction of broadband internet would help the industry.
Roberts said the cruise sector offered huge opportunities but New Zealand had to attract more infrastructure investment.
"The China market continues to evolve at a rapid pace," he said.
"One hundred million Chinese will travel overseas this year, and that is expected to double to 200 million by 2020," he said.
"We need to keep thinking about who we are targeting in China and in emerging markets, because every other destination is also eyeing these big prizes."
Big spenders
• Tourism is New Zealand's second biggest export earner at $10.3 billion or 15.3 per cent of foreign exchange earnings in the year to March.
• International tourists spent about $1.2 million an hour and domestic tourists $1.5 million an hour.
• Tourism directly or indirectly supports 8.3 per cent of total employment in New Zealand or 166,800 full-time equivalent jobs.
• The Tourism 2025 growth framework has a goal of almost doubling total revenue to $41 billion a year by 2025.