Republic of Ireland international Forde has a year left on his contract and is a reported target for Premier League Hull following a fine season for the Lions.
But new Den chief Lomas hopes to persuade the 33-year-old, a former team-mate from their days at West Ham, to stay put in south London.
He said: "I know Fordey from when he was a young kid at West Ham and all credit to him. He didn't get an opportunity so he went back to Ireland, he had the right mentality and then came back with Cardiff.
"He's built himself up to be Ireland's number one now, he had a great season last year and obviously you want to kep your best players.
"David has a year left and we'd certainly like to keep him for the foreseeable future. But there are a few players with a year left and that's a challenge for me, to sit down and prove to them that Millwall are going in the right direction.
"It certainly would have to be a hell of a bid for us to even contemplate getting rid of David Forde."