The Rugby Park outfit have been linked with the Saints number one as they seek to strengthen the position ahead of next season.
Inverness' Antonio Reguero is close to finalising a pre-contract agreement that will see the Spaniard join Killie on a two-year deal.
Shiels is keen to find another goalkeeper but says Mannus is not one of the names on his wanted list and that he is not preparing to make a swoop.
He said: "Definitely not, that wasn't mentioned.
"I think he's a great goalkeeper and I always did think that. But people have just plucked that out of the air because he's from Northern Ireland.
"There have been no approaches made for the goalkeeper. I didn't even know he was out of contract."
With Cammy Bell set for a move to Rangers and Kyle Letheren released last week, Shiels is keen to bolster the goalkeeping position.
He added: "Yes we will be looking at that. I've got a few irons in the fire so to speak."
On Reguero's deal, he said: "It's almost there."