Australia's pesticides assessor is three months late delivering its report that reconsiders a chemical banned in other countries and linked to brain damage in children.

Key points: Chlorpyrifos is a popular insecticide recently linked to adverse health impacts

Chlorpyrifos is a popular insecticide recently linked to adverse health impacts The farm chemical regulator has missed its own chlorpyrifos review deadlines

The farm chemical regulator has missed its own chlorpyrifos review deadlines The body was forced to move to Armidale by the Government in 2016 and has suffered staff losses

The report is the culmination of a 22-year process reviewing the health impacts of chlorpyrifos, a popular insecticide used in fruit and vegetable farming.

The Australian Pesticides and Veterinary Medicines Authority (APVMA) had planned to deliver the report as part of its reconsideration process in September 2017.

However it revised its work plan and amended the deadline to August 2018.

The organisation is now saying the report will be released in early 2019.

An APVMA spokesperson blamed the delay on "the complexity of interpreting scientific information, particularly the epidemiological data", that is, the extent of health impacts caused by the chemical.

Within the organisation, just 15 per cent of chemical reconsiderations were finalised on schedule during 2017-18. The stated goal is 100 per cent.

APVMA has suffered staffing losses due to the 2016 decision by former agriculture minister Barnaby Joyce to move the organisation from Canberra to Armidale, inside Mr Joyce's electorate.

The organisation declined to address whether this had contributed to the delay.

What is chlorpyrifos?

Chlorpyrifos attacks the nerve system of insects but is also toxic to humans.

Some studies have linked exposure to the chemical to adverse brain development in unborn children.

There are 135 products with chlorpyrifos currently registered with APVMA. No other company has more than Dow Agroscience's 10 listings.

Taimor Hazou from Dow said chlorpyrifos was a "critical pest management tool" used by growers to manage pests that can destroy crops.

"Regulatory bodies in 79 countries have reviewed the science, carefully evaluated the product and its significant benefits and continued to approve its use."

Its use is common around the world, although some countries such as South Africa and Sweden have barred its use.

An August court decision in the US instructed the Environment Protection Agency to cancel its registration, but the Department of Justice requested a re-hearing.

Mr Hazou was asked whether Dow was confident chlorpyrifos would maintain its registration in Australia.

He declined to comment, instead saying "we will continue to support the growers who need this important product."

Regulator first recommended review 22 years ago

In 1996 the National Registration Authority — the previous name for APVMA — nominated chlorpyrifos for review for reasons including concerns about its human toxicity and US restrictions on its use.

An interim review prepared in 2000 found that children were not at an increased risk from chlorpyrifos products "that are used according to label instructions".

The label for chlorpyrifos products was updated with new use, first aid and safety directions at the time. The report also recommended "data gaps" be filled in subsequent research.

A preliminary review of new data in 2009 also led to more changes to the label and restricted its domestic use.

Supplementary assessments were ordered in 2015 as part of a new work plan. This set a deadline for the final report, which has now passed.

The plan states regulatory decisions — such as suspending or cancelling its registration — are to be made following the delivery of the final report.