sydney australian prime minister malcolm turnbull say wednesday government future risk lose sydney by-election weekend fail regain one-seat majority force rely independents survive power turnbull conservative voter base harbourside seat bennelong usually safe blue-ribbon seat collapse accord opinion poll tuesday newspoll australian newspaper say turnbull liberal-national coalition opposition labor 50 percent chance win two-party prefer vote liberal voters desert newly form conservative party tight race high cost labor win bennelong labor leader bill shorten would close become prime minister turnbull tell reporters sydney turnbull lose bennelong would take loss support key independents vote confidence see minority government topple centre-left labor hold power since 2013. turnbull lead minority government since october deputy prime minister force quit parliament hold dual citizenship australia constitution national politicians australian citizenship deputy prime minister re-elected dec. renounce new zealand citizenship turnbull fail regain one-seat majority bennelong liberal incumbent former tennis champion john alexander quit parliament believe might hold dual australian-british citizenship turnbull future rest voters affluent bennelong electorate 13 percent electors bear either china hong kong strain relations australia china past week may cost turnbull vote turnbull announce last week ban foreign political donations aim prevent external influence domestic politics single china announce ban prompt rebuke china people daily newspaper australia must recognise china lead world government attitude towards china cost vote say cao gui dong candidate christian democrat party bennelong loss bennelong would also see turnbull grip prime ministership come scrutiny one liberal politician already call quit christmas turnbull fight leadership speculation 2017 amid slump poll voters flock far-right party vow lead government next election due 2019 version story fix typo paragraph six australian pm say government risk lose sydney by-election