The Irishman, who arrived at Tannadice from Middlesbrough in 2011, has established himself as a key player at the Scottish Premier League side.
He is out of contract at the end of the current campaign but manager McNamara is keen to keep hold of the 27-year-old and is planning talks with the club's chairman.
He told the Daily Record: "Willo has been excellent in the past two games. Of course, I would like to keep him longer come the end of the season.
"I will sit down with the chairman and Willo's future will be on the agenda, along with that of a few others."