The Conservatives have zero tolerance for sexual misconduct, the deputy prime minister has told Sky News after claims the party covered up for a "serial rapist" MP.
He urged anyone with accusations of criminality to "go straight" to the police.
Mr Dowden was speaking after a report in the Mail On Sunday that former Tory chairman Sir Jake Berry had sent a letter to police in which he revealed a number of allegations about an MP had been made known to the party, but little action had been taken.
Sir Jake had only become aware of the claims when he learned the party had paid for one of the alleged victims to receive treatment at a private hospital.
His letter, written jointly with former chief whip Wendy Morton, another MP and a Downing Street official, also claimed the failure of others in the party to act had allowed the politician at the centre of the allegations to continue offending.
Responding to the latest revelations, Mr Dowden said: "Any allegation of sexual misconduct I take extremely seriously and the Conservative Party has zero tolerance for sexual misconduct.
"We have an independent complaints mechanism and that investigates any allegations.
"The Mail on Sunday, as far as I can tell, doesn't contain any details of the persons involved. So there's a limit to what can say further than that, other than say it may be the case that these matters are subject to an ongoing criminal investigation.
"So to reassure you we take any allegations exceptionally seriously."
Pressed over whether there was a wider problem at Westminster after a series of scandals, Mr Dowden said: "No, I don't think there's something wrong about our parliament and the vast majority of people in parliament are there to serve their constituents and to serve the nation.
"Now, in respect of a very small number of cases, it's important robust action is taken.
"And indeed, if there are allegations, I would urge anyone to go straight to the police as a criminal matters and they should be investigated."
It is the latest in a string of sexual misconduct claims to hit the Conservative party.
At the end of last month, senior Tory MP Crispin Blunt was suspended by the party after being arrested on suspicion of rape and the possession of controlled substances - allegations he denies.
It came after former Conservative minister Peter Bone was suspended from the Commons for six weeks after a claim he exposed himself to a member of staff was upheld.
Chris Pincher, the former deputy chief whip, was sacked and eventually resigned after being accused of groping two men in a Tory private members' club.
And last year, former MP Imran Ahmad Khan was jailed after being found guilty of sexually assaulting a 15-year-old boy.