* Govt says protests have damaged cross-party relations
* Opposition says demonstration still on
DJIBOUTI, March 3 (Reuters) - Djibouti has ordered its opposition to postpone an anti-government protest set for Friday after a previous rally turned violent, a cabinet minister said on Thursday, as a wave of political unrest sweeps north Africa.
Opposition supporters have been calling for the departure of President Ismail Omar Guelleh, in power since 1999 and facing mounting opposition after he oversaw a change to the constitution that allows him to seek a third term in office.
The opposition says it has been galvanised by the success of regional protest movements such as those that toppled the long-serving rulers of Egypt and Tunisia this year.
Mohammed Daoud, head of the opposition Djibouti Party for Development, told Reuters Friday's peaceful demonstration would take place as planned and the government was bent on denying a free and fair election in April.
Interior Minister Yacin Elmi Bouh said last month's clashes, which killed at least one protestor and one policeman -- and the opposition's failure to condemn the violence -- had damaged what he called a spirit of partnership and trust between the government and opposition.
"In this difficult environment, with the painful consequences of the last round (of protests) still raw ... I ask you to change the date of this protest to another time," the minister said in a statement.
Daoud, one of three opposition leaders briefly detained after the Feb. 18 clashes, said: "There is a political motive to this order and that is to organise elections by force, by repression."
Djibouti's tiny size belies its strategic importance to Western allies. It hosts America's only military base in Africa and France's largest military camp on the continent.
Foreign investors have rewarded Djibouti's stability. DP World-run DPW.DI Djibouti Port aims to become a leading regional shipping hub and is already used as a major sea gateway by landlocked neighbour Ethiopia. [ID:nLDE62L1LZ]
The former French colony's port is also used by foreign navies patrolling busy shipping lanes in the Gulf of Aden to fight piracy.
Sixty-three-year-old Guelleh's People's Rally for Progress party has ruled since independence from France in 1977. Djibouti is ranked by the United Nations as one of the world's poorest nations and unemployment runs at about 60 percent. (Reporting by Abdourahem Arteh in Djibouti and Richard Lough in Nairobi; Writing by Richard Lough; Editing by David Clarke)