Tasmanian Senator Jacqui Lambie has described the Palmer United Party's plans to sue her as "hurtful", saying the party's leader, Clive Palmer, promised not to launch legal action against her when she quit the party last year.

The Palmer United Party (PUP) announced today it was suing Senator Lambie and Senator Glenn Lazarus to recoup $9 million it spent on their election campaigns.

Both have quit the party in recent months, with Senator Lazarus planning to serve out his six-year term as an Independent and Senator Lambie announcing she has formed her own political party, the Jacqui Lambie Network.

PUP national director Peter Burke issued a statement today saying the two senators promised to represent the PUP for the entirety of their terms when they sought endorsement at the 2013 election.

"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 his 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 said it spent $7 million on Senator Lazarus' Queensland election campaign and more than $2 million getting Senator Lambie elected in Tasmania.

Legal action has 'good chance': Palmer

The PUP's leader, Clive Palmer, told the ABC he believed the legal action had 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."

When asked if the pair had signed a contract giving this guarantee, Mr Palmer said "there were documents signed" and the two senators had publicly promised to serve out their terms with the PUP through the media.

Senator Lambie reads an email from Clive Palmer advising he is taking legal action against her. ( ABC News: Emily Bryan )

However Senator Lambie has disputed that, saying she had no idea what documents Mr Palmer was referring to.

She has described the legal action as hurtful, saying Mr Palmer gave her an assurance that he would not sue her.

"If there was one thing he did promise me when I left the party last year, when we had a one-on-one, was that he'd never sue me and that he was very proud of the way I'd performed and he was grateful to have had me as a part of his party," she said.

The Tasmanian Senator said she had not received any formal notification of the legal action and was seeking advice from both her lawyers as well as Senate officials.

"Well considering it's April Fools' Day, I wasn't quite sure whether it was for real or not, but I certainly haven't been sent any legal papers or documents as such, so I'll just sit and play the waiting game," she said.

"I intend to get some advice, some legal advice, and I'll get advice from the Clerk of the Senate about possible contempt of Parliament because as far as I'm concerned, no one's allowed to interfere with the free and fair performance of a senator.

"In the past, threatening Members of Parliament with legal action have been ruled as a contempt of Parliament so whether or not this issue will eventually be referred to the Ethics and Privileges Committee, we'll see."

The Democratic Labour Party has launched a High Court bid to oust Victorian senator John Madigan from his seat after he quit that party in September.

Mr Palmer recently flagged joining that case but today he said his party was not "actively considering it" at the moment.

"That was one of the options," he said.

"We're not suing [Senator Lazarus and Senator Lambie] in relation to whether they can hold their Senate seat or how they should vote, that's a matter for them.

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

The ABC has contacted Senator Lazarus for comment.

Lambie forms JLN to give 'ordinary Australians' chance to run

On Tuesday, notices of Senator Lambie's application to register her party appeared in Tasmanian newspapers.

The advertisement listed the "proposed registered officer" as Jacquiline Lambie and the abbreviated party name as JLN.

Announcing the new party, Senator Lambie said JLN would start by focusing on recruiting candidates to run for Senate spots, but would field candidates for both federal and state elections.

She said she wanted to establish her own political party to give "ordinary Australians" a chance to enter 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."