The information ministry said in a statement read on national television that Jammeh was planning to remain in office until the Supreme Court decides on a petition he filed.
Jammeh is challenging the result of the Dec. 1 presidential election he lost to Adama Barrow.
Barrow, a former real estate agent who was little known before he announced his candidacy, meanwhile has also reiterated he is planning to take office on Jan. 19, as scheduled.
Earlier this week, Gambia’s dysfunctional Supreme Court adjourned hearing Jammeh’s petition to Monday, since only one of a required minimum of five judges were present.
Experts however believe it will be highly unlikely that four additional judges will be present on Monday.
This is because the Supreme Court has not been operational since Jammeh fired several of the court’s judges in mid-2016.
All other eligible Court of Appeal judges left the country after the December election.
Observers fear that delays to the planned hand-over of power could lead to violence as Gambia has been in a political lockdown since Jammeh refused to accept the result.
Meanwhile, some West African leaders, including Nigeria’s President Muhammadu Buhari, are expected to arrive in Gambia to convince Jammeh to respect the constitution and hand over the presidency.