* Planning Minister Bellerive designated prime minister
* Dismissal of previous premier followed criticism
* U.N. mission urged quick nomination to keep stability (Updates with designation of new prime minister)
By Joseph Guyler Delva
PORT-AU-PRINCE, Oct 30 (Reuters) - Haitian President Rene Preval on Friday designated his planning and cooperation minister to be prime minister of the poor Caribbean state after the Senate dismissed the previous premier.
Economist Jean Max Bellerive, who is respected by diplomats and international donors, will replace Michele Pierre-Louis who was voted out of office by the Senate early on Friday after lawmakers faulted her performance in promoting economic recovery. She had been in office just over a year.
"The president of the Senate, Kely Bastien, has just received the letter in which President Preval has designated Jean Max Bellerive to become the new prime minister. Now it is official," Senator Nenel Cassy of Preval's ruling Lespwa party told Reuters in a telephone interview.
Bellerive's designation as premier must be approved by both chambers of parliament -- the Senate and Chamber of Deputies -- after his credentials for the job are scrutinized.
The swift nomination by Preval followed an appeal by the U.N. peacekeeping mission in Haiti that a successor to Pierre-Louis be named quickly to avoid political and economic instability in the poorest state in the Americas.
Development experts say some 70 percent of Haiti's population of 9 million live on less than $2 a day, making it the poorest state in the Americas.
The Senate ousted Pierre-Louis by a simple majority of 18 of its 29 members. Opponents of the move called it unconstitutional and said lawmakers had no power to remove the head of government without explicit instructions from Preval.
The U.N. mission praised Pierre-Louis for her response to a series of devastating hurricanes in 2008 and what it called her spirit of constructive collaboration with Haiti's international partners.
"The adoption of this censure motion comes at a critical time of efforts to achieve political, economic and social stabilization of the country," the mission known by the French acronym MINUSTAH said in a statement.
"It is therefore essential to proceed without delay to the installation of a new prime minister and a new government team to avoid any risk of a return to a period of instability that could hinder the encouraging prospects that have emerged recently in the fields of investment and job creation."
Pierre-Louis had rejected accusations that she failed to use effectively millions of dollars made available through an oil discount agreement with Venezuela to repair buildings and roads damaged in storms last year.
But Senator Joseph Lambert, a member of Lespwa, said she had done nothing to improve living standards since she was appointed head of government.
Pierre-Louis' removal was likely to disappoint Bill Clinton, the former U.S. president and U.N. special envoy for Haiti who had been counting on political stability to attract foreign investment to help develop the poor Caribbean state.
Four hurricanes and tropical storms pounded the country last year, killing some 800 people, devastating crops, washing away bridges and flooding seaside towns.
Clinton surprised some analysts early in October by telling an investor conference in Port-au-Prince that Haiti's political risk was lower than it had ever been in his lifetime.
Some 9,000 U.N. troops and police keep the peace in Haiti, which has a history of violence and instability.
Five years ago, a president was overthrown by armed rebels and 18 months ago, food riots toppled another prime minister.
Haiti's recent history has included a popular uprising that toppled the 30-year Duvalier family dictatorship in 1986, a military coup that ousted President Jean-Bertrand Aristide in 1991 and years of gang violence and political tumult.
Clinton and institutions like the Inter-American Development Bank have been hoping to lure new business to reactivate the Haitian economy, especially in areas like agriculture and textiles.
Haiti won $1.2 billion in debt relief from the World Bank, the International Monetary Fund and other creditors in July, freeing up $50 million a year to spend on other projects. (Editing by Pascal Fletcher and Peter Cooney)