Brown was elected to the Australian Senate for Tasmania in 1996, and was an outspoken voice in opposition to the conservative government of John Howard, and in support of green and human rights issues, including international issues such as Tibet, East Timor and West Papua. He also introduced bills for constitutional reform, forest protection, to block radioactive waste dumping, to ban mandatory sentencing of Aboriginal children, to prohibit the use of cluster munitions and for greenhouse abatement.