Pauline Hanson: Anti-immigration politician wins four Senate seats
Australia's prime minister must negotiate with 11 crossbenchers to pass laws through the country's upper house.
The Australian Electoral Commission announced the final Senate results for all states and territories on Thursday.
To secure the 39 votes it needs to pass laws, the ruling conservative coalition needs support from the crossbench.
This includes four far-right One Nation senators and three from the anti-gambling, pro-protectionist Nick Xenophon Team.
The upper house also includes independents Jacqui Lambie and Derryn Hinch, conservative Family First Senator Bob Day and libertarian David Leyonhjelm.
Prime Minister Malcolm Turnbull declared victory in the lower house on 10 July after the opposition Labor Party conceded defeat.
A strong swing against the government at the closely fought election left doubts about its agenda and Mr Turnbull's leadership.
Senate votes typically take several weeks to count - especially where the results are extremely close - because postal votes can take up to 13 days to arrive.
Opposition Leader Bill Shorten attributed the election of Ms Hanson and her colleagues to voting reforms and the prime minister's decision to call a double dissolution.
"The presence in such numbers of One Nation in the Senate is a direct result of Mr Turnbull and Mr Di Natale's action in terms of their so-called electoral reform," Mr Shorten said.