A lawyer says imprisoned Nobel Peace laureate Liu Xiaobo will make a formal complaint seeking a retrial to overturn his guilty verdict.

Liu is five years into an 11-year prison term for his conviction on a charge of subversion, after he authored and disseminated a document calling for democracy. Liu has insisted he is innocent.

Mo Shaoping said Tuesday that Liu agreed to the legal challenge during a prison visit by his wife in October. Mo said he and a fellow lawyer have requested to meet Liu to discuss details but are awaiting a decision from the local jurisdiction where Liu is locked up.

Liu was awarded the peace prize in 2010 for two decades of nonviolent struggle for civil rights. Beijing has condemned the award.