West Brom are thought to have seen a seven-figure bid for the Scotland international rejected last week.
The likes of Everton and Southampton are also thought to be keeping tabs on Robertson's situation, but McNamara insists the club are under no pressure to sell the highly-rated defender.
"It was nice to hear the chairman had knocked that back because Andy is a very good player and I want him here next season," McNamara told the Dundee Evening Telegraph.
“I know the club doesn’t have to sell and the chairman’s decision confirms that.
“It doesn’t surprise me that other clubs are interested but we want to keep him.”
Meanwhile, McNamara has conceded they have may have to sell winger Gary Mackay-Steven this summer rather than risk losing him for nothing at the end of the season.
Highly-rated midfielder Mackay-Steven is out if contract next summer and a number of English clubs are thought to be tracking the former Liverpool youngster.
McNamara admits they may have to cash in on the 23-year-old if they fail to tie him down to a new contract.
"He is going into his last year so that is something we must think about," added McNamara.
"We've spoken to him and will keep doing that but it would be disappointing if he stayed another year and walked away for nothing.
"This is not about us looking to move him on. It depends on who is interested. That is a lot to do with it."