He has become the third MP referred to a Conservative disciplinary committee, after being accused of pressuring a young researcher to go on a date with a businessman who was 'older than her father.'
Mr Kawczynski is alleged to have approached the woman in 2013 on behalf of a contact from overseas who had seen her in Parliament.
He denied the allegations and vowed to clear his name.
Mr Kawczynski said: "The allegations I believe were made by Channel 4 by an unknown third party, and I am looking forward to working with the code of conduct process to clear my name.
"I strongly deny the allegations made. I approached her see if they would go for a coffee with a friend of mine but that is all I have done.
"This will have to be challenged and the due process has to take place."
At least five Tory MPs are now under investigation, with Charlie Elphicke also suspended from the party and referred to the police.
Backbench MPs Mr Kawczynski, Daniel Poulter and Stephen Crabb are all being investigated by the party committee while ministers Damian Green and Mark Garnier are being looked at by the Cabinet Office.
A Conservative spokesman said: "The chief whip has referred Daniel Kawczynski to the party's new disciplinary committee for further investigation."