In a new paper, she has proposed bringing together oceanographers, data scientists and other marine experts to create a sophisticated new ocean observing system.
Its benefits could include everything from being able to predict coastal hazards and oil spill trajectories to tracking plastics in the ocean and making assessments of fisheries stocks.
"New Zealand is managing multiple stressors including sea level rise, ocean acidification and impacts from changing terrestrial fluxes," O'Callaghan said.
"A sense of urgency exists to understand, predict and mitigate nationally the ocean's responses to these problems.
"Climate change is making its presence felt in New Zealand waters with marine heatwaves, increasing ocean acidification and sea level rise."
Ocean conditions are monitored by a number of groups, including science institutions such as Niwa, Cawthron Institute, regional councils and port authorities.
Examples included two sea surface temperature monitoring sites at opposite ends of the country, an ocean acidification observing network with 14 sites around New Zealand, wave buoys, monitoring buoys such as the one in Wellington Harbour and coastal moorings.
Typically, buoys could deliver a combination of data on currents, waves, salinity, temperature, oxygen, chlorophyll, ocean acidity and wind but the data can be difficult to access or researchers may be unaware it exists.
O'Callaghan said there were also some large areas where little was known about ocean conditions, particularly on the west coast of the North Island and parts of the east coast around Hawke Bay and Gisborne.
"Some councils have monitoring buoys but in terms of how the coastal waters interact with the deeper ocean, the science is poorly understood," she said.
"The idea is to do a better job of pulling together existing observations and connecting them across organisations so we all know where they are and making sure they are accessible.
"Then it's figuring out how to translate what we have learnt from existing platforms to make appropriate and cost-effective observations in places we don't have a lot of information."
A unique component of the proposed network is the aim to incorporate traditional Mātauranga Māori knowledge into the plan in a bid to develop more effective ocean stewardship.
O'Callaghan said a new ocean observing system would ideally be funded by central government but in the short term, planning would come from individual organisations until a business case could be developed.
There were, however, some major new efforts under way to fill in some of the most crucial blanks.
One was the just-launched Moana Project - an $11.5m collaboration that aimed to make New Zealand a world leader in ocean-forecasting capability.
Much of the open-access data behind its models would be amassed by high-tech, low-cost instruments mounted on fishing vessels.
Data collected by these smart sensors – being developed with help from Nelson-based firm Zebra-Tech – would feed into real-time models, observing ocean temperatures and other factors.
And another new programme, just awarded a million-dollar grant through the Government's Endeavour Fund, would use state-of-the-art machine-learning technology to better predict the risk of coastal storm surge.
Earlier this year, researchers polled New Zealand marine scientists to pinpoint the biggest priorities for ocean science.
Their paper narrowed down 10 key questions across nine areas: fisheries and aquaculture, biosecurity, climate change, marine reserves and protected areas, ecosystems and biodiversity, policy and decision-making, marine guardianship, coastal and ocean processes, and other anthropogenic factors.
Those questions ranged from what impact ocean acidification would have on marine resources, and where and how should we set up more marine protected areas, to how trawling and dredging could be affecting productivity on continental shelves, and how we could pick up "tipping points" in ocean ecosystems before it was too late.
