The 20-year-old's contract with the Mariners expires in May but the A-League club are not prepared to let him go on the cheap.
"It is disappointing that these private commercial discussions are in the public arena, but I can confirm Hull City are one of a number of clubs to have expressed an interest in signing Mathew Ryan in January," club chairman Peter Turnbull told the Sydney Morning Herald.
"Hull have tabled an offer for Mat as a result of his good form in the A-League, selection for the Socceroos as well as his undoubted potential.
"Negotiations with Hull are still at an early stage, however we will continue to talk with them and several other clubs over the coming weeks in order to arrive at the best possible outcome for Central Coast Mariners and Mathew."
Ryan was named A-League Goalkeeper of the Year last season and had trials with West Brom and Tottenham earlier in the year.
Hull certainly seem to be in the market for a goalkeeper as they are also linekd with Rune Almenning Jarstein of Viking.
Viking say an English club has made a bid, with reports suggesting it is Hull.
"Yes, I can confirm that we have had a dialogue and now got an offer from a club in England," director Arne Larsen Okland told TV