The Turnbull Government will need the support of nine of those 11 to pass any legislation Labor and the Greens oppose.
Before Prime Minister Malcolm Turnbull called what was supposed to be a strategic double-dissolution election for last month, (july) the Coalition had 33 representatives in the Senate.
Now, it has 30.
Labor has one additional senator, with 26 seats, and the Greens are down one to nine.
The crossbench has grown from eight to 11 senators.
One Nation has four and the Nick Xenophon Team three.
Family First's Bob Day and Liberal Democrat David Leyonhjelm have been re-elected, along with Jacqui Lambie, who has formed the Jacqui Lambie Network.
And broadcaster-turned-senator Derryn Hinch will be in the upper house, representing the Derryn Hinch Justice Party.
The Coalition figures to face tough negotiations with the crossbench when it wants to pass bills both the Greens and Labor oppose.
But Opposition Leader Bill Shorten says Malcolm Turnbull only has himself to blame for the make-up of the new Senate.
Mr Shorten blames the situation on Mr Turnbull and the Greens supporting changes to Senate voting.
"Pauline Hanson's One Nation party appears to have four senators. They have four senators because because the Greens political party and Malcolm Turnbull changed the rules in the Senate and then Malcolm Turnbull called a double dissolution. The presence in such numbers of One Nation in the Senate is a direct result of Mr Turnbull and Mr (Greens leader Richard) Di Natale's actions, in terms of their so-called electoral reform."
After winning an unexpected two seats in Queensland, the One Nation Party has become the fourth-largest force in the upper house, behind the Coalition, Labor and the Greens.
One of those newly elected One Nation senators is Malcolm Roberts, known as a climate-change skeptic.
He says he wants to amend the Racial Discrimination Act to allow frank and fearless discussion about what he regards as the main issues confronting Australia.
"We need people to speak up freely and deliver what they really believe, and, yet, they get slammed for that. And I'm looking at (Section) 18C under the Sexual ... under the Racial Discrimination Act. That needs to be addressed, because that is curbing free speech. And when we have free speech curbed, it means we don't talk about the real issues: tax, Islam, terrorism."
Nick Xenophon says he will negotiate with anyone in the Senate, including One Nation, wherever their interests coincide.
"Well, where I don't share common ground with Pauline Hanson is in relation to immigration, in relation to race and religion, and, particularly, her views on Islam. But if she's concerned about issues of Australian jobs, about Australian manufacturing, about the sale of farming land under current rules -- which many are concerned are simply too lax, in terms of our foreign-investment framework -- I'll work with her. But, you know, similarly, the Greens have had similar views on the sale of farming land."
Greens Leader Richard Di Natale says he is concerned the rise of One Nation as an influential voice in the upper house could undermine Australia's multicultural fabric, though.
"We'll make sure that we tackle all of those issues in a way that makes Australia a fairer, more decent, more compassionate place. When it comes to issues like racism, we, as a nation, have got a long way to go. And, no doubt, we'll continue to see those calls from One Nation senators to target people from different backgrounds, different ethnic communities, and we will take a very strong stand against that."
