Household pesticides may cause some of the intellectual development problems in children previously associated with lead, an Australian toxicologist says.

In a commentary available online in the journal Science of the Total Environment, Professor Brian Gulson says there is no question lead has a detrimental effect on children's intellectual development.

But the Macquarie University researcher says several studies have shown similar effects in children exposed to low levels of organophosphate pesticides.

He says the similarity in effects and the overlap in timing of the major use of these pesticides in the community and lead exposure studies could have resulted in confusion.

But his comments have been dismissed as an "interesting idea" that is "not well supported" by the science.

They come as regulatory bodies in the US, Canada and Australia are reviewing guidelines for acceptable levels of lead in the blood.