The futures of Defoe and Sigurdsson have been the subject of speculation with Spurs in the market for striking reinforcements.
Defoe has been linked with a host of clubs, including West Brom and QPR, while Sigurdsson struggled to hold down a regular place in the side last season.
However, Villas-Boas insists that he has no plans to offload the duo and that they are still in his long-term thoughts.
"They are players we count on 100 per cent," Villas-Boas is quoted as saying in the Daily Express. "Sigurdsson is completely in our plans.
"Defoe is a hero for Tottenham and has been doing well. He faces competition which he has always faced during his career."