Medical experts are concerned about the introduction of a new test for cervical cancer.

Health Minister Jonathan Coleman announced the new molecular-based test will be implemented within two years and will replace the current liquid-base cytology testing.

Otago University Associate Professor and cancer researcher Brian Cox said the new tests pick up HPV much earlier - but that might not always be a good thing.

"The problem with detecting it early is that many of the HPV infections actually resolve by themselves."

He said this will greatly increase the need for colposcopy services which we couldn't cope with.

Mr Cox believes we shouldn't just replace the current test, and said we should look at all the options.

"To avoid the risks of leaping from one screening test to another, there is an opportunity to do co-testing for a period of time," he said.

He said by testing the same sample with different tests they can assess how the test will prevent cervical cancer and demand on services.