Clive Palmer says his former party colleague Jacqui Lambie is a victim of lobbyists.
Senator Lambie has quit the Palmer United Party and will sit as an independent.
Mr Palmer says Senator Lambie is being manipulated by a lobbyist for Tasmania's poppy industry and a former Queensland state MP turned lobbyist.
"Being in parliament should be about public service not serving ourselves," he told Fairfax Radio on Monday.
Mr Palmer said he had not considered whether he would take legal action against Senator Lambie to recoup "hundreds of thousands" of dollars spent on her 2013 election campaign.
But an internal party investigation will continue.
He rejected suggestions his party had lost clout, saying it was still the biggest bloc of votes in the Senate.
"We still have a voting agreement with the Motorists (Senator Ricky Muir)," he said.
"There's nothing much changed really - Jacqui Lambie is just one senator."
Mr Palmer said when people got into parliament for the first time, it tended to go to their heads.
"The power, the notoriety, the media, all that sort of stuff," he told Fairfax radio.
"They think they can become prime minister."
Mr Palmer said as a PUP member, Senator Lambie got notoriety because the party had the balance of power but as an independent, she would find it more difficult to get media attention.
"That's what she craves," he said.
