Everyday products such as shampoo and dishwashing powder are putting dozens of toddlers in hospital every year.
A new report on hazardous substances shows that injury rates for youngsters are three times higher than other age groups.
In 2014, the most recent year analysed, there were 70 children aged under 5 who were hospitalised as a result of hazardous substances.
Environment Minister Nick Smith said hospitalisation rates for under-5s had dropped by 30 per cent since data collection started in 2006, to 23 per 100,000.
"There are still too many people ... being injured," Smith said.
"Toddlers are still the most vulnerable ... many injuries occur because products such as ... oven cleaners are left within reach of young children."
Smith said the issue was personal - his only hospitalisation occurred as an MP after he inadvertently used paint stripper as a mouth wash after a tradesperson left the product in the bathroom of his Wellington flat.
The injury burned his throat and vocal chords.