The Independent Electoral Commission (IEC) was sealed off without warning by security forces on the same day President Yahya Jammeh's political party lodged a court case against the commission to have a recent election result annulled.
A decree issued today claimed the authorities had received reports the IEC would be burnt down, stating: "Now that the threat has abated, the IEC head office will reopen."
IEC staff could return to work "with immediate effect", the statement added, but a visible security presence would be maintained around the compound close to the capital, Banjul.
The president's legal complaint against the IEC was triggered in part by a vote recount in the days following the December 1 election, which ultimately confirmed opponent Adama Barrow's victory, 22 years after Jammeh took power.
The Gambia is facing prolonged political deadlock as Jammeh has said he will await a Supreme Court ruling, delayed until January 10, before ceding power.
Court sources say six foreign judges have now been appointed by Jammeh to serve on the Supreme Court to hear his complaint, joining the sole sitting judge already on the bench.
The reopening of its headquarters will allow IEC officials time to prepare their case.
The president's stance has stoked international concerns about the future of the tiny west African country, with the UN joining African leaders in calling for him to step down.
Meanwhile the Thursday decree also hit out at the tide of false news circulating on the internet and social media that claimed Jammeh had been deposed by his army chief.
"The Gambia under the leadership of His Excellency the President Sheikh Professor Alhaji Dr Yahya A.J.J. Jammeh Babili Mansa will continue to jealously guard the stability of the nation and ensure the maintenance of peace and security," the decree said.