The Mariners chairman moved to dismiss reports the coach's move to the Sky Blues was already decided, revealing there was an improved deal from the club on the table
Arnold led the Mariners to the Premiers' Plate in the 2011-12 A-League season, but - with his club's financial battles well publicised - has been heavily linked with a move to rivals Sydney FC.
Reports surfaced on Saturday that Arnold had sealed deal to join the Sky Blues for the 2012-13 campaign, but Mariners chairman Peter Turnbull moved on Monday to shoot down the speculation.
Arnold will be on the touchline for Central Coast in their AFC Champions League match against Tianjin Teda on Tuesday, and it seems there is no decision on his future as yet.
"There has been a substantial amount of media speculation recently suggesting that Graham Arnold has already signed with Sydney FC," Turnbull wrote in an open letter to the club's fans.
"In fact, what is true is that Sydney have tabled a very substantial offer for ‘Arnie’, which he is considering. However, we have recently lodged what we consider to be a very attractive counter-offer and have been speaking with Graham at every available opportunity.
"What must also be remembered is that in the case of the Mariners, we have had finals series football and the AFC Champions League to play in recent weeks. As such, we have needed to be mindful not to interfere in any way with the teams’ preparation as we have a clear desire to excel in every competition in which we compete.
"Our offer for Graham Arnold to remain as head coach of our club is for an increased amount, and for an additional season. Ultimately, it will be Arnie’s decision, and whatever decision he makes we will support him, as we do with all our coaches and players. That is the nature of our club."
Former Australia manager Arnold has established himself as one of the A-League's most sought-after managers since taking over the Mariners for the 2010-11 season, leading the club to the A-League grand final in his first season at the helm.