Toornstra has been linked with a move to Swansea in recent weeks.
He told NUSport: “If Swansea are (interested), then I would take that chance. It’s a nice club and they play Dutch football.”
AZ Alkmaar and FC Twente are also reportedly interested in the midfielder.
Toornstra’s current contract at ADO Den Haag is set to expire in the summer of 2013.