Young and Downing have been linked with moves to Manchester United and Tottenham respectively during the past week but Houllier will only offload players he feels are not part of his plans and has been given the green light to bring in new signings next month by chairman Randy Lerner.
When asked if Downing and Young would be sold, Houllier said: "No. No way. Categorically no."
He added: "The chairman reassured me (there will be money to spend) although I've got everyone coming back.
"But I can tell you that at some stage, if we need some players in, we will take them."
Houllier intimated that defender Richard Dunne and midfielder Stephen Ireland will soon be back in his plans as he looks for a positive reaction against Chelsea following the 4-0 mauling at Manchester City.
Houllier said: "At some stage there will be (a way back for them), sooner rather than later.
"They are out of the team only on footballing reasons. They weren't performing at times."
Source: PA
Source: PA