WELLINGTON - The number of New Zealanders being hospitalized with infectious diseases has surged in the last two decades, say researchers in a warning that the government must do more to understand the links between global warming and public health.

More than a quarter of acute hospitalizations in New Zealand are resulted from infectious diseases, compared with only 18 percent in the early 1990s, said a statement from the University of Otago Sunday.

"A warmer, wetter and stormier climate has the potential to make this burden of serious illness significantly worse because of the biological and ecological origins of many infectious diseases. This potentially means both additional human suffering and additional costs to the tax-payer funded health system," said Nick Wilson, Associate Professorof the university's department of public health.

A study conducted by the university showed "significant gaps in our knowledge" of the connections between climate change and infectious diseases, said Wilson.

Much more effort should be made by government agencies and researchers into the possible increase of infectious diseases because of climate change.

"While climate change is having impacts on the environment, it is also critical to understand its current and potential impacts on human health, including infectious diseases," said Wilson.

One of the highest priorities identified by the study was the need for better understanding of the risk of mosquito-borne diseases, such as dengue fever, carried by insects from tropical countries. Many New Zealand habitats could be colonized by new mosquito species as temperatures and rainfall increased, it warned.

The New Zealand government had spent around 70 million NZ dollars ($57.43 million) on eradicating the southern salt marsh mosquito in recent years, so it was important to maximize prevention efforts to protect health and to save costs, Wilson said.

Studies had indicated that food-borne salmonella was also related to warmer temperatures, said Wilson.

However, the links between increased temperature or rainfall to diseases caused by campylobacter, cryptosporidium and severe E-coli infections were much less clear.

If increased rainfall and flooding did occur, then it was likely that many communities without reticulated water supplies would be more vulnerable to water-borne diseases.

The increase in serious skin infections causing hospitalizations could also be linked to warmer temperatures and higher humidity. "This is another area that urgently needs further research," said Associate Professor Michael Baker, co-author of the study.

The review also found that New Zealand government agencies had little information on their websites about climate and health. Only one of five relevant agencies had a document related to climate change and health, and the document was published in 2001.

The authors reported that one research project was underway on the climate and health issue in New Zealand, but this only covered some of the potential diseases.

"Given the potential scale of the climate change problem, New Zealand dramatically needs to lift its response in this area," said Wilson.