Sissoko and Lamela have had difficult seasons at Spurs this term, with neither finding their top form.
Sissoko only arrived at Tottenham from Newcastle United last summer, but the French international has struggled to justify his price tag.
The powerful midfielder has failed to break into Mauricio Pochettino’s side’s starting line-up.
And Le Tissier said: "I always thought this was a strange signing and he doesn't strike as a Tottenham kind of player and hasn't been a roaring success, so I think if they can get a decent chunk for him then let him go.”
Lamela, too, has found things difficult this year - but he has previously proven his quality at White Hart Lane.
The Argentine was growing into a key player for Spurs, but he has missed much this campaign with injury.
And Le Tissier claims that Lamela’s time at Tottenham should be brought to an end at the conclusion of this campaign.
"I'd say he's flattered to deceive,” the Southampton legend said. “I know he's been injury a lot this season but I think he's just a little bit too flaky. Yes he's got ability but I haven't seen it quite enough."