Australia has blocked Huawei Technologies of China from bidding on contracts in the $38 billion Australian National Broadband Network, citing security concerns, Huawei said Monday. “We were informed by the government that there is no role for Huawei” in the network, said Jeremy Mitchell, a spokesman in Australia for Huawei, one of the world’s largest suppliers of telecommunications equipment. The Australian plan is the largest infrastructure project in the country’s history. It is intended to connect 93 percent of homes and workplaces with fiber-optic cable, providing broadband service in urban and rural areas. It was announced in 2009 by the Australian government with a committed investment of as much as $38 billion. The network is expected to be ready by 2020. The Australian Financial Review newspaper said in a report Monday that Huawei had sought to secure a supply contract worth as much as 1 billion Australian dollars, or $1.05 billion, as part of the project, b