By Mark John BRUSSELS, Sept 11 (Reuters) - NATO Secretary-General Jaap de Hoop Scheffer will ask German Chancellor Angela Merkel on Thursday for more help in alliance efforts to train Afghanistan's national army, an alliance official said. At the centre of the talks in Berlin is the delicate question of whether Germany will allow military trainers to accompany Afghan soldiers into the southern heartlands of the Taliban insurgents. NATO's role in the breakaway Serb province of Kosovo will also be on the agenda of the visit. NATO wants to accelerate training of Afghan army cadets both to take the strain off its 40,000-strong International Security Assistance Force (ISAF) and as part of a longer-term strategy eventually to pull out of the country. The alliance hopes a new strategy of embedding trainers directly in Afghan units will boost the effort. But Germany and a number of other countries are reluctant for their trainers to accompany their charges into the south, where the fighting is toughest. "The key question is will their trainers go south," said a NATO official ahead of the Berlin talks. "If a country can't send its trainers south, doesn't that hobble the training effort somewhat?" added the official, who spoke on condition of anonymity. The debate has echoes of an alliance dispute last year in which the United States and allies with troops in south Afghanistan such as Britain, the Netherlands and Canada called on other nations to take a greater share of the fighting. CORRUPTION Germany, France, Spain and Italy finally agreed to offer support when needed, but stipulated such deployments would be "in extremis" and not become the norm. The Taliban are leading a dogged insurgency four years after being ousted from power. The Afghan army training effort is all the more vital given growing domestic pressure on Canada and the Netherlands to scale back their presence or pull out altogether. Results of the training programme so far have been patchy. According to one internal alliance estimate, 37,000 Afghan soldiers have been trained up out of a target of 70,000 by 2010. with only 25,000 seen fully ready for action. The United Nations recently cited corruption in army ranks as a factor undermining the fight against the huge Afghan opium industry. De Hoop Scheffer's talks with Merkel and other top German officials come weeks before German parliament must decide whether to extend the deployment of the 3,000-plus German soldiers in ISAF and six Tornado reconnaissance jets. Despite calls by a number of left-wing lawmakers to bring the troops and planes home, alliance officials are confident the mandate of the German troops will be extended. The talks in Berlin may also cover German concerns about a possible unilateral declaration of independence by Kosovo's ethnic Albanians if last-ditch mediation to produce a deal between them and Belgrade fails by a Dec. 10 cut-off date. German officials fear the lack of a new U.N. mandate could raise questions over the legitimacy of foreign troops in any newly independent Kosovo. NATO officials and a number of alliance members believe the existing U.N. Security Council resolution 1244 would continue to apply and de Hoop Scheffer has repeatedly stated that the alliance will remain in Kosovo for as long as needed. (additional reporting by Ilona Wissenbach)