The Palmer United Party (PUP) is seeking to sue its former senators, Glenn Lazarus and Jacqui Lambie, for the money spent on their election campaigns.

PUP founder Clive Palmer spent millions of dollars backing prospective senators around the state, and now that two of his successful bids have backed away from the party, Palmer wants his money back.

Lazarus and Lambie both quit the party in recent months, but will still serve their six-year terms.

PUP national director Peter Burke says that two senators pledged themselves to the PUP for the full length of their terms.

“Relying on those promises, the party spent millions of dollars and thousands of party supporters worked hard to get Mr Lazarus and Ms Lambie elected,” Mr Burke said in a statement.

“They have now broken their promises and the party will seek to recover in the courts - under the principle of promissory estoppel - those party funds.”

The party claims to have spent $7 million on Senator Lazarus' election campaign in Queensland and over $2 million getting Lambie elected into her Tasmanian Senate seat.

Mr Palmer has told the ABC that he has a “pretty good” chance of success.

“It was a typical promise, a reliance on that promise and then they broke their promise,” he said.

“The law is, if that happens, it's called 'promissory estoppel', you don't get any damages and you don't get any interest but you're entitled to your money back.

“We're suing them just to recover the funds that we spent in reliance of their promise before they got elected.”

Mr Palmer alleges that “there were documents signed”, and the two senators had pledges to serve their terms with the PUP during interactions with the media.

Meanwhile, Senator Lambie has applied to register a new party – the Jacqui Lambie Network.

She says the JLN will give “ordinary Australians” a shot at politics.

“First and foremost I want these people to be able to put their state first,” she said.

“I don't want people dictating to them on how they should vote ... and I want them to be able to make sure that their state always comes first and their country right next to that.

“That's why it's called a network, it's not called a group or a party. I want people to keep their individuality. I want them to do the best possible job that they can.

“Running around as an independent costs a lot of money. It doesn't matter how hard you try, when it comes to taking on the major parties, money-wise, you can't compete with them.”