Iniesta's current deal runs out at the end of the season and talks have been going on for some time regarding an extension, leading to reports suggesting he is contemplating an exit next summer.
However, Bartomeu is confident the Spain international will pen fresh terms after revealing the club legend will be offered a "special" deal that represents his status at the Camp Nou.
"The agreement with Iniesta will be special, different for being him," he told 8TV. "I am not going to reveal it because they are aspects of the negotiations, but with Ramon Sostres, his representative, we have talked for a while and we will continue advancing because the will of both parties is to continue.
"Iniesta is a benchmark not just for us, but also for the youngsters. He knows that we want him to play here for as long as he wants because he has earned that right. We have seen in these days that Andres is fundamental for the club and Ernesto Valverde counts on him.
"We are talking with his agent with the desire that it will be an indefinite contract so that he finishes when he wants."