Twelve people are dead after a record outbreak of a disease linked with heavy rain in a flood-hit region that is again on cyclone watch.

The melioidosis death toll in far north Queensland has more than doubled in a week, with more than 50 cases reported in the Cairns region and more in and around Townsville.

The soil-borne disease has emerged as another threat to locals mopping up after record flooding as Cyclone Alfred looms.

Recovery efforts are underway in north Queensland after record-breaking February rainfall triggered floods that claimed two lives and forced hundreds to evacuate.

The clean-up continues as authorities track Cyclone Alfred, which is expected to develop into a “severe” category three system by Wednesday.

Another concern is the “very alarming” rise in melioidosis cases, a wet season disease spread through contact with contaminated water, soil and air.

There have been 53 cases of the so-called “mud bug” in Cairns since January, mostly among the elderly or people with diabetes, chronic diseases or receiving cancer treatment.

There have a further 34 cases in Townsville.

“It absolutely is a record-breaking year,” Tropical Public Health Services director Jacqueline Murdoch said on Tuesday.

“We haven’t seen anything like this, and the numbers are very alarming.”

Cairns authorities announced last week four people had died from the disease.

Since then another there have been a further five fatalities.

Another three people have died from the soil-borne disease in Townsville since flooding inundated the north in February, authorities revealed last week.

Murdoch said the number of deaths was alarming but consistent with the risks of melioidosis.

“It’s a very severe disease and it has a reasonably high fatality rate, so we do have a large number of deaths now, which is reflecting the large number of cases,” she said.

Melioidosis symptoms include fever, pneumonia, exhaustion, vomiting, abdominal pains or chest pressure.

Authorities are investigating the high number of cases but suspect hot temperatures and high rainfall have contributed.

Murdoch urged Queenslanders to wear boots, masks and long pants when cleaning up as a precaution.

“People really need to be careful about being outside in heavy rain, being in contact with soil, and certainly anybody using a high-pressure hose should be wearing a mask,” she said.

She said anyone with a cough or difficulty breathing should seek immediate medical help.

“It is a very serious disease and it can progress very quickly,” she said.

Latest modelling for Cyclone Alfred, as at Wednesday morning. Image: Bureau of Meteorology

North Queensland is already on high alert with Cyclone Alfred sitting about 950 kilometres off Mackay.

The cyclone is slowly moving south-east while intensifying and is tipped to become a category three system early on Wednesday.

Several scenarios are possible from Friday, including Alfred tracking closer to the Queensland coast. Locals have been urged to monitor the latest forecasts and warnings.

Cyclone Alfred’s only impact on the Queensland coast so far is gusty winds and showers for coastal communities from K’gari (formerly Fraser Island) north to Cairns.

If the cyclone tracks toward the coast it may trigger more rainfall just as scientists count the cost of the recent deluge on the Great Barrier Reef.

Record rainfall pushed vast amounts of river runoff to the reef, forming extensive flood plumes, James Cook University’s TropWATER scientists said.

Satellite imagery revealed the full extent, with flood plumes stretching more than 700 kilometres along the coast and up to 100 kilometres offshore.

Flood plumes reduce light to coral reefs and seagrass, slowing their growth and can lead to bleaching and disease.

The surge of water into the reef contained freshwater, sediment, nutrients and contaminants from farms and urban landscapes.

Meanwhile, Cyclone Bianca off Western Australia in the Indian Ocean is expected to weaken into a low-pressure system by Wednesday and not affect the mainland.

-with AAP