Manchester United and Real Madrid are interested in the 24-year-old winger, but Tottenham insist the Wales star is not for sale.
Iceland international Sigurdsson, 23, believes Bale will stay at Tottenham and said keeping him would help manager Andre Villas-Boas bring in other good players.
"He is important from that point of view. Good players want to play with other big players," Sigurdsson said.
"It's a big club and hopefully he'll stay and we'll bring in a few other good players.
"He's a great player and if he stays it will be fantastic. I'm sure he will stay.
"The players here talk about the season (2009/10) they got into the Champions League and how fantastic it was.
"Then missing out when Chelsea won the Champions League and being fifth last season was extremely disappointing."
Tottenham enjoyed a strong 2012/13 English Premier League season, finishing fifth - a point behind Arsenal.
Sigurdsson hopes the club's additions in the off-season in Paulinho, Nacer Chadli and a couple of others make them even stronger.
"You never know how it will pan out. Manchester United have changed their manager for the first time in a very long time," he said.
"It'll be interesting to see how that goes. There could be a couple of other teams fighting for the title and there's going to be about six teams fighting for the Champions League places."
