Beijing admits it is facing a huge challenge to reopen quake-blocked roads and other infrastructure. Mu Hong, a deputy director of the National Development and Reform Commission, the top planning authority, said three roads near the epicentre were still blocked while other roads that had reopened were under constant threat from landslides and falling rocks. 'It remains an arduous task to reopen roads between Yingxiu and Wenchuan , between Wolong and Yingxiu, and between Beichuan and Mao counties,' he said. Most roads were reopened only temporarily and would be put to another test in the imminent flood season, Mr Mu said. Authorities were also trying to reach many mountain villages and towns that had yet to receive food and energy supplies, and to restore telecom services. Mr Mu said reconstruction would take a long time. Officials plan to map a comprehensive rebuilding plan in three months and hope the main construction could be finished within three years. Despite the devastation in an area that is a supplier of agricultural products, Mr Mu said it would not have much impact on the country's economy, food supply or inflation. 'Sichuan accounts for only 4 per cent of China's overall gross domestic product,' he said. 'The areas hit by the quake account for less than 1 per cent. It will have an impact on the national economy, but it will be rather limited.' He dismissed suggestions the country's economic macro-control policies should be adjusted to ease the impact of the quake. Shi Gang , another reform commission official, said grain supply would not suffer. 'In Sichuan, 92 per cent of the wheat has been harvested,' he said. 'So we expect this year's summer harvest will be rather good.' Mr Shi said: 'The conditions for maintaining stable grain prices are favourable, and it's unlikely to create a major impact on the consumer price index.'