By Jerry Norton BANDA ACEH, Indonesia, Dec. 4 (Reuters) - Problems that keep thousands living in temporary shelters in Indonesia nearly two years after a tsunami wiped out their homes need to be resolved by the end of 2007, a top U.N. recovery official said on Monday. Indonesia's Aceh province was hardest hit among areas in the region affected by the Dec. 26 Indian Ocean tsunami. The disaster left some 170,000 dead or missing in Aceh and displaced half a million people. Of 128,000 permanent homes required for the displaced, only 43,400 have been built, according to U.N. figures. Aside from some 12,000 families still in barracks, thousands more are in transitional shelters or staying with other people. "The housing issue, basic human shelter, has to be solved by the end of 2007," Eric Morris, U.N. recovery coordinator for Aceh, told Reuters in an interview. "I think there are concerns that it may go over a bit, to 2008, but I think at this stage it's quite important ... let's try and make it by the end of 2007." One barrier to getting people into permanent housing has been the difficulty in establishing land titles. The tsunami destroyed a large number of property records, and many people in Aceh, on Sumatra island's northern tip, lacked clear titles to start with. Former U.S. President Bill Clinton, in his role as U.N. special tsunami envoy, stressed in a visit to Aceh on Saturday the need to "remove backlogs and speed up the land titling process, so that hundreds of thousands of Acehnese obtain the security of title that they so deserve." Getting more people in permanent housing on their own land could help resolve other challenges of the recovery process like a lack of good jobs, Morris said. By one estimate the tsunami wiped out 600,000 jobs, with fisheries, agriculture and small trade sectors among those most affected. "I think that there's a relationship between provision of housing and land and creation of sustainable livelihoods. Once people have those assets they then move on to create new assets and to generate money," Morris said.