Syria on Saturday hailed the formal lifting of sanctions by the United States as a "positive step" that will help its post-war recovery.

"The Syrian Arab Republic welcomes the decision from the American government to lift the sanctions imposed on Syria and its people for long years," a foreign ministry statement said.

The United States lifted comprehensive economic sanctions on Syria on Friday, marking a dramatic policy shift following the December overthrow of Bashar al-Assad and opening the door for investment in the country's reconstruction.

The ministry described the move as "a positive step in the right direction to reduce humanitarian and economic struggles in the country."

It formalised a decision announced by US President Donald Trump during a visit to Saudi Arabia earlier this month.

The sanctions relief extends to Syria's new government with conditions the country not provide safe haven for terrorist organisations and ensure security for religious and ethnic minorities, the US Treasury Department said.

US Secretary of State Marco Rubio said the waiver would "facilitate the provision of electricity, energy, water and sanitation, and enable a more effective humanitarian response across Syria". (AFP)