According to a club statement, Town reluctantly agreed to terminate Oar's contract at his request.
Speaking to the club's website, the former Brisbane Roar winger praised the side who currently sits in 7th in the Championship.
“I’d like to thank Ipswich Town for their co-operation over ending my contract,”
“It’s a great club and the manager, staff and players made me feel very welcome but while I have enjoyed playing for Ipswich, I have found it difficult to settle into life in England.
“I have been away from home for five or six years now. My family came over at Christmas and maybe I’ve got to a point where I want to be closer to home again.
“It’s just one of those things where moving over here as not worked out as I had hoped but I’d like to wish the Club, the manager, the staff and the players the best of luck over the rest of the season and I hope to be watching Ipswich in the Premier League next year.”
Town boss Mick McCarthy added: “Tommy came to see me and said that he hadn’t settled in England and asked if it was possible to end his contract.
“It’s disappointing obviously as we had high hopes for him. He had shown great quality in training but I don’t want to keep a player at the Club who doesn’t want to be here. We wish him well.”
Oar has played nine matches for the club since joining in August from FC Utrecht for a fee or around $3 million, scoring one goal.