Liberal Jim Molan has blamed factional leaders for creating the preselection model which led to him missing out on a safe Senate spot at the next election.
Senator Molan hit back at claims by former Liberal MP Fiona Scott he had supported the voting system which led to his demise.
"The reforms that were enacted (the Bennelong motion) were introduced by faction leaders," he said in a statement on Monday.
"Our reformers wanted every NSW member to vote on upper house preselections, centralised and decentralised. Instead, the Bennelong constitution gave power to the state council where factional interests are strongest."
The Bennelong Motion, which was agreed to in February, gave party members a say in preselections for the lower house, but left the state council in control of the Senate.
Tony Abbott on Monday described Senator Molan's relegation as "absolutely nauseating" and derided a "factional power play".
The former prime minister told 2GB radio he was "a little bit bamboozled" as to how Senator Molan, a former major general in the Australian Army, was relegated to an unwinnable spot on Saturday.
Hollie Hughes and Andrew Bragg were placed ahead of the conservative Senator Molan on the Liberals' NSW Senate ticket.
Senator Molan, who replaced Nationals MP Fiona Nash after she was embroiled in the dual citizenship crisis in 2017, placed third in the Liberal pre-selection.
However, he will be bumped to fourth under a coalition deal that gives the Nationals the third senate position.
"Thank you to the thousands of my supporters who have reached out this morning," Senator Molan tweeted on Monday.
"I will endeavour to reply to each and every one of you as soon as I can. Your kind words are overwhelming."
After his defeat, Senator Molan pulled out of Monday night's scheduled appearance on the ABC's Q&A program.
