WorkSafe NZ was now auditing adventure businesses, although that process is taking longer than expected and operators had been granted a one month extension to finish the inspection job.
Those in breach of the new regulations risked being fined thousands of dollars a day.
Key said there was always risk in some activities but they needed to be operating within a well-regulated regime .
In 2010 British media ran stories on deaths in New Zealand, prompting a push by Key to tighten rules.
"There's only so long that my office can fend of inquiries by international media."
He said New Zealand's tourism market faced hot competition from other destinations and risked losing visitors if they didn't feel safe here.
Key said the broader tourism industry would be helped by a fall in the New Zealand dollar which has dipped below US78c. While this wouldn't necessarily mean more tourists would come here, they would spend more when the do visit.
Tourism is New Zealand's second biggest export earner (behind dairy) earning $10.3 billion or 15.3 per cent of New Zealand's foreign exchange earnings in the year ended March 2014.
One issue that operators are concerned about is the auditing of adventure activities. The deadline for approval had to be extended because of problems getting all businesses checked off.
Tourism Industry Association chairman Grant Lilly said every hour of the day international tourists spent about $1.2 million an hour and domestic tourists $1.5 million an hour.
"It's happening all over New Zealand..... and supporting communities where there are few other opportunities....
It is estimated that tourism directly or indirect 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 tourism revenue to $41 billion a year by 2025.