Popular Welcome Bay swimming spot Kaiate Falls has been given a permanent health warning after officials failed to find the cause of the bacterial contamination that has been a feature of the site in recent months.

A health warning was first issued in January, and Medical Officer of Health Dr Phil Shoemack has now made that warning permanent.

Kaiate Falls has seen its health warning upgraded to permanent. Photo: File.

Ongoing water monitoring by the Bay of Plenty Regional Council shows high levels of bacterial contamination at Kaiate falls and the stream.

The council insist they have done extensive testing of the wider catchment upstream from Kaiate Falls, but no one source has been identified.

Regional council is working with land owners to reduce agricultural sources, says Phil.

The permanent health warning advises against recreational water contact with Kaiate falls and stream.

'Contamination of recreational water can cause a number of illnesses such as gastroenteritis - a diarrhoea and vomiting illness,” says Phil.

The warning posted in January was because of high levels of faecal coliform bacteria.

Officials at the time said regional council would be checking agriculture or stock access.

The Kaiate Stream headwaters originate in bush a relatively short distance away in the Papamoa hills.

The main stream crosses a kilometre or so of farmland before flowing beside the road for a short distance.