Pezeshkian has raised the idea of moving away from Tehran before, with rainfall in the capital this year at its lowest level for a century.

"The reality is that we have no choice. It (the relocation) is a necessity. We cannot overwhelm this region with more population and construction," he said, according to the official IRNA news agency.

"We can develop, but we cannot solve its water problem."

The Iranian president warned earlier this month the current capital could be evacuated without rainfall before winter, though he did not elaborate.

Tehran nestles on the southern slopes of the Alborz mountains and has hot dry summers usually relieved by autumn rains and winter snowfall.

The mountain peaks, usually already covered in snow at this time of year, are still dry.

Faced with water shortages, the government has decided to cut off water supplies periodically to Tehran's 10-million-strong population to limit consumption.

Pezeshkian's evacuation idea had drawn some criticism, including in local media. The reformist Ham Mihan newspaper branded his remarks a "joke".

The government later said the president only intended to warn residents that the situation was serious, rather than present a concrete plan.

Last week, Iranian authorities announced the launch of cloud seeding operations to induce rainfall.

Pezeshkian has since last year identified traffic congestion, water shortages, resource mismanagement and severe air pollution as the key reasons to relocate the capital.

In January, government spokeswoman Fatemeh Mohajerani said authorities were studying a possible relocation to the Makran region, a largely underdeveloped area on the country's southern coast.

While no concrete plans were announced, that proposal also drew criticism.