The Egyptian government has been asked by the UNESCO to submit a detailed report on the restoration work that was carried out at the 4,600-year old Djoser pyramid following reports that the pyramid had been damaged.
Egyptian media reported earlier this month that the pyramid, which dominates the necropolis of Saqqara, southwest of Cairo, has been damaged during the restoration work.
"The UNESCO World Heritage Centre sent a letter to the ministry of antiquities requesting a detailed technical report on the work," said Tamar Teneishvili, a senior official of the UN Educational, Scientific and Cultural Organisation in Cairo.
"This request was made after information gathered from the media," Teneishvili told AFP.
She said UNESCO would wait for the ministry's report to decide on its future plans.
UNESCO has also asked if its own 2011 recommendations on the restoration of the pyramid had been followed.
Several Egyptian NGOs have criticised the restoration work, saying the monument's original facade has been altered.
Some specialists have also said that the company hired to do the restoration work, Al-Shurbagy, does not have the necessary experience.
Antiquities Minister Mamdouh al-Damati has rejected the criticism as "baseless".
Last week, he told a group of journalists invited to see the ongoing restoration that the "work is underway without a problem".
The executive director of the project, Michel Ghobrial Farid, has also rejected the criticism, saying the pyramid's appearance was restored the way it was at the time of its construction.
The reconstruction project started in 2006 but was interrupted in February 2013 due to a lack of funding.
The tomb, built by the master architect Imhotep for the Pharoah Djoser, stood 62 metres (203 feet) tall originally and is considered the oldest building in the world built entirely of stone.