On a global scale, introduced marine species pose a significant threat to marine environments. Within this paper four challenges to delivery of marine biosecurity outcomes are identified, with a brief discussion on how these challenges are being me within the New Zealand context. Currently within New Zealand, only 3% of the total biosecurity funding is expended on the marine environment. To be effective with such a small component of the total budget, marine biosecurity has directed research into six programmes: 1) risk profiling; 2) compliance monitoring of ballast water exchange; 3) alternative management tools for marine vector threats; 4) baseline information to support border control; 5) surveillance for marine pests; and 6) incursion response options and systems. At present, the marine biosecurity system developed in New Zealand offers a good example of an outcome-oriented system that balances costs and benefits across economic, environmental, social and spiritual values. The short-term costs to establish such a system may be significant however; the long-term benefits far outweigh the initial investment+