Located in the Saqqara necropolis in the ancient city of Memphis, some 30 km south of Cairo, the step pyramid is made up of six mastabas (rectangular structures) stacked on top of each other.
Designed by architect Imhoteb, the vizier of Djoser, the pyramid includes a 28-metre deep burial chamber for the pharaoh who some scholars believe ruled Egypt for almost two decades.
The 60-metre-high pyramid underwent extensive restoration, including filling gaps in the mastabas with blocks similar to the originals. The burial chamber, the ceiling of the central shaft and the pyramid's narrow internal passages were also renovated.
"Studies carried out in 2003 showed that the world's oldest stone building was in real danger," Egypt's tourism and antiquities minister Khaled Khaled el-Anany told reporters, saying the restoration project had cost the country 104 million Egyptian pounds (roughly $6.6 million).
"The restoration project started at the end of 2006 but slowed down after 2011. Real work was only resumed at the end of 2015, and here we are," he added, referring to repeated delays caused by the turmoil that gripped Egypt following its famous uprising nine years ago.
Mohamed Youssef, director of the archaeological Saqqara area, told ABC News that tourists will be allowed to enter the pyramid for the first time via its southern entrance.
Egypt has made a number of discoveries and concluded several restoration projects in recent months as it seeks to shore up its vital tourism industry, which took a hit following the 2011 revolution that unseated autocrat Hosni Mubarak.In July last year, Egypt opened two other pyramids for visitors -- the Bent Pyramid and its satellite pyramid in the nearby Dahshur royal necropolis.