British police are investigating the deaths of 88 people in the UK who bought products from Canada-based websites allegedly offering lethal substances to people at risk of self-harm.

The probe is part of international inquiries sparked by the arrest in Canada earlier this year of Kenneth Law, who has been charged with two counts of counselling and aiding suicide.

Canadian police say Law, from the Toronto area, used a series of websites to market and sell a substance commonly used to cure meats that can be deadly if ingested.

Police said Law was suspected of sending at least 1200 packages to more than 40 countries.

Authorities in the United States, Italy, Australia and New Zealand also have launched investigations.

In June, it was reported the Australian Federal Police, Australian Border Force and state police knew of at least 10 packages containing the lethal substance that had been sent to Australians, resulting in deaths. At the time, the AFP declined to comment or either confirm or deny it was investigating.

Britain's National Crime Agency said it has identified 232 people in the UK - 88 of whom had died - who bought products from the websites in the two years to April.

The agency said it was investigating whether any crimes had been committed in the UK but that "at this early stage there are no confirmed links between the items purchased from the websites and cause of death in any of these cases".

"Our deepest sympathies are with the loved ones of those who have died," National Crime Agency deputy director Craig Turner said.

"They are being supported by specially trained officers from police forces."

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