Saeed Namaki inaugurated the plant's production line, located in Alborz province, via video conference, the government website reported.

"Today we witness the inauguration of one of the most important projects since the (Islamic) revolution with the joint investment of Iran and Denmark," he said.

Namaki expressed hope that Iran could soon become a "drug distribution and production centre" for the Middle East.

The Danish pharmaceuticals giant has sold its products in Iran since 2005 through its subsidiary, Novo Nordisk Pars.

It signaled its intention to construct the 70 million euro ($83 million) facility in 2015 and said it would take five years to complete.

That announcement followed an agreement reached between Iran, Britain, China, France, Germany, Russia and the United States in the same year, promising Iran sanctions relief in exchange for restrictions on its nuclear program.

But the deal has been on life support since US President Donald Trump unilaterally withdrew from the accord and reimposed sanctions on Iran in 2018, dashing hopes for foreign investment in the country.

Drugs and medical equipment are technically exempt from the US sanctions, but purchases are frequently blocked by the unwillingness of banks to process purchases for fear of incurring large penalties in the United States.

According to the head of Iran's food and drug administration, Iranian diabetic patients require 800,000 insulin pens per month.

"Procuring insulin is significantly foreign currency-intensive and is made harder during the difficult time of sanctions," Mohammadreza Shanesaz told Mehr news agency.

Novo Nordisk has promised to save Iran 25 million euros in the first year and 45 million euros in the second after production starts, he added.