New South Wales Premier Barry O'Farrell has issued a statement expressing disappointment that claims of inappropriate sexual conduct by a senior minister have been broadcast.

Allegations that a minister was seen to have been engaging in a sex act in public were broadcast on Thursday night on Channel Nine.

Police have confirmed they have questioned a number of people over an incident.

"Police have spoken to a number of people in relation to allegations of inappropriate behaviour by a 62-year-old man," they said.

"No information was provided to police in relation to any offence having occurred. As a result, no further police action is proposed."

In a statement, Mr O'Farrell said he was disappointed that anyone could have their reputation damaged by unsubstantiated allegations.

"In the absence of any formal complaint or further information, it is grossly unfair to smear anyone's reputation," he said.

The Premier says if anyone had any information that could help police, they should come forward.

ABC/AAP