A former Cook Islands Health Minister says it's time for the country to increase its health spending, particularly for the outer islands.

Nandi Glassie has been conducting PhD research into the health and economic reforms of the 1990s and their effects.

He said money spent on health as a percentage of GDP has fallen each year since 2012.

Mr Glassie was the health minister for most of those years of decline.

However, he said his calls didn't amount to hypocrisy, because the health system was still in good shape.

He said some spending had to be reined in, but now there's a healthy surplus to allow for more spending.