UPDATED 8:34pm: The Prime Minister says there's no conflict of interest problem as family troubles impact on one of his cabinet ministers.

It's been reported by Fairfax that the brother of a sitting minister is due before the Courts to face child indecency charges.

John Key says the minister in question came to him as soon as they were made aware of the situation, and was willing to step down if needed.

"The advice I've received is that there is no conflict of interest, and the issue can be managed. So people appreciate that cabinet ministers, like anybody else, have family...I'm quite confident that the position can be managed."

Earlier this year, Labour leader Andrew Little stood social development spokeswoman Carmel Sepuloni down from her portfolio while her mother was before the courts on welfare fraud charges. Mr Little said at the time that was because of Ms Sepuloni's portfolio and reinstated her as soon as her mother was sentenced.

Mr Key said there were different views on the need for that and in this instance the advice he received was "very thorough and that advice very clearly is to follow the action I'm taking."