The COVID-19 pandemic could hit drug markets just as the 2008 economic crisis did, seeing a rise in the use and trafficking of narcotics as well as exacerbating the risks for users, the UN drugs and crime agency (UNODC)  warned on Thursday.

In its 2020 World Drug Report, the virus was predicted to lead to an overall increase in drug use with a shift towards cheaper consumption and injecting, which carries greater risks for users.

It also warned that countries were more likely to further reduce drug-related budgets and to give less priority to anti-trafficking operations and international cooperation in the wake of the pandemic.

The poor and disadvantaged people were more easily to turn to illicit activities linked to drugs, either production or transport due to a lack of opportunities and the rising unemployment, the report said.

"The COVID-19 crisis and economic downturn threaten to compound drug dangers further still, when our health and social systems have been brought to the brink and our societies are struggling to cope," UNODC Executive Director Ghada Waly said.

She also called on all countries to show greater solidarity and provide support to help some developing countries tackle illicit drug trafficking and offer evidence-based services for drug use disorders and related disease.

The pandemic comes on the back of a trend of already rising drug use, especially in developing countries, with UNODC finding 269 million people in 2018 had used drugs at least once, up 30 percent from a decade earlier.

"This is a very alarming increase. Not just the increase in the amount of people using drugs, but there are more youths, adolescents, children using drugs," Waly warned on Thursday.

Border closures and other measures linked to the virus have already caused shortages of drugs on the street, leading to higher prices and reduced purity, the report said.

Drug traffickers seemed to be relying more on maritime routes, including continuing direct cocaine shipments by sea from South America to Europe, but also now transporting drugs via rivers rather than roads in Latin America, UNODC official Angela Me told a press conference.

The report, which mostly examined data up to early 2019, said the use of cocaine and methamphetamine was rising, with growing methamphetamine markets in Afghanistan and Iraq.

Global cocaine production again reached an all-time high, continuing its record-setting trend.

Me also noted how the market in addictive drugs had become "bigger and more complex" because of an increasing number of substances being abused, some of which are currently legal.

Cannabis remains the most widely used drug worldwide with an estimated 192 million users in 2018. But opioids used by around 58 million people, remained the most harmful.