KHARTOUM: Printers delivered hundreds of thousands of registration books for Sudan's southern independence referendum on Sunday, clearing a major hurdle in delayed preparations for the vote, organizers said. Voting is due to start on Jan. 9, 2011 in the referendum, promised in the 2005 peace deal that ended decades of north-south civil war, on whether southerners want to stay in Sudan or secede. Preparations are lagging badly and there are fears that delays, arguments over the sharing out of revenues from the oil produced in the south, and growing north-south tensions over the vote may re-ignite conflict. Washington has stepped up diplomatic pressure on Khartoum to hold the vote peacefully and on time. Influential US Senator John Kerry was due to meet Sudan's vice president and other ministers on Sunday at the end of a three-day trip to Africa's largest state. South African printers flew 500,000 voter registration books to Khartoum on Sunday, enough for southern voters living in Sudan's 15 northern states, said the spokesman of the referendum's organizing commission, Jamal Mohamed Ibrahim. Millions more will soon arrive in the southern capital Juba, he added. “This is a giant step forward ... When the materials are around everyone feels confident that these things are going ahead,” commission deputy chairman Chan Reek Madut told Reuters from Juba. The commission has already started training referendum registration staff, and organizers still hope to start voting on Jan. 9, he added. “That is our hope and it is our aim,” he said. Under an earlier timetable set out in legislation governing the plebiscite, the whole registration exercise should have been completed three months before the vote. In a new, contracted timetable issued by the commission this month, voters will now be registered between Nov. 14 and Dec. 1 and the final list of voters will be published on Jan. 4, just five days before the start of voting. The commission still has to print voting forms and Sudan has not yet appointed a commission to organize a simultaneous referendum, promised under the same peace deal, on whether the central disputed Abyei region should join north or south Sudan.