Coronavirus-related border controls, lockdowns and flight shortages are making illegal drugs more expensive and difficult to obtain around the world, the United Nations Office on Drugs and Crime said in a report published on Thursday.

The pandemic is having a mixed effect on drug production in different regions and on smuggling by air, land and sea, but the overall trend in countries where drugs are consumed appears to be relatively uniform, the UNODC said in the report on COVID-19, the respiratory illness caused by the new coronavirus.

"Many countries across all regions have reported an overall shortage of numerous types of drugs at the retail level, as well as increases in prices, reductions in purity and that drug users have consequently been switching substance (for example, from heroin to synthetic opioids) and/or increasingly accessing drug treatment," the report said.