Plaid Cymru's MP Liz Saville Roberts is attempting to change the law and make it an offence for politicians to publish false or misleading statements, which has led to MPs being asked today to back the Bill.
So far Ms Roberts has had cross-party support but she will tell the Commons that MPs need to support her Bill in order to "defend democracy, serve the public, and protect the basic standards by which we should all live".
The Plaid Cymru Bill - called the Prohibition of Deception Bill - would make it an offence for politicians to wilfully lie to the public.
She says the piece of legislation would allow the politician who has "willfully lied" an opportunity to correct their lie.
If they fail to do this, it would then be taken to the police and the Director of public prosecution to decide whether further punishment should be considered.
Repeated offences would be sanctioned with a fine or, stopped from standing for election for up to 10 years.
It would affect MPs and members of the Welsh Senedd, Stormont Assembly (in Northen Ireland) and Scottish Parliament, as well as Police and Crime Commissioners and elected mayors, who could all be convicted of making “false or misleading statements” but not councillors.
Ms Saville Roberts says that Plaid Cymru has been involved in putting this idea forward for 18 years.
She told ITV Wales' political programme Sharp End: "It goes back to the Plaid Cymru party leader Adam Price when he was in Westminster in 2006. When it was proposed that Tony Blair was misleading the parliament then."
"People do believe that politicians lie and I would say that is extremely bad for our democracy," she said.
"I would also say the methods that hold politicians in check are entirely voluntary and they are in the hands of the ruling party and government."
Ms Saville Roberts said we have legislation in place to stop commercial businesses from misleading the public and so we should have the same laws in place for our leaders.
"They [Westminster] depend on codes of honour that come from the 19th century", she added.
"We wouldn't expect commercial businesses to do this. We have laws in place to stop businesses from selling goods or selling services that are inaccurate.
"We wouldn't expect doctors to lie to their patients."
In an ITV Wales poll, the public was asked if it was ever acceptable for a politician to lie, and over 80% said "no".
When asked if it's okay for politicians to avoid telling the truth, 63% said "no" but 29% said it was "sometimes okay".
Ms Saville Roberts thinks the precautions we currently have in place to stop politicians from lying "isn't working."
She said: "If the present arrangement for politicians rewards the liar more than it rewards the person who is correcting a mistruth, then what else should we do?
"We now live in an age, where mass misinformation is everywhere. We need to ensure our game is as clean as possible and that we have a duty of candour.
"The cost of lying is something really fundamental to our values of democracy. It is our duty to change that culture that has taken hold."