Nonetheless, the election is expected to take place on 8 April as scheduled.
Sources in the capital, Djibouti City, said pro-Guelleh posters and other campaign materials were being plastered on walls and circulated throughout the city on Friday.
Guelleh was elected as the second president of the tiny Horn of Africa nation in 1999, taking over from his uncle, Hasan Aptidon, who had ruled the country since it gained independence from France in 1977.
Aptidon was forced by international pressure to introduce multi-party politics in 1992, ending 15 years of one-party rule in Djibouti, which has a population of just 712,000, according to the UN.
Parliamentary elections were most recently held in 2003, with Guelleh's Union for Presidential Majority coalition winning all 65 seats amid opposition claims of widespread rigging.
The main opposition coalition, the Union of Democratic Alliance (UDA), has called upon all its members to boycott April's election.
Another opposition group, the Front for the Restoration of Unity and Democracy (FRUD), released a statement on 18 March supporting the UDA's decision, and stating that "change through the ballot box is almost impossible in the Republic of Djibouti".
FRUD, which boycotted the 2003 elections, launched an appeal to the people of Djibouti "to get mobilised against the presidential election", according to its statement.
Djibouti was a French colony
It also called upon states with a military presence in the country, namely France and the US, to back "a democratic transition in Djibouti".
Djibouti served as an operations base during the 1990-1991 Gulf war, and France continues to have a significant military presence in the country.
More recently, the US has stationed hundreds of troops in Djibouti as part of its effort to counter terrorism in the region.
Muhammad Dawud Chehem, the only other candidate in the presidential election, reportedly dropped out of the race earlier this month due to financial problems.