Guardiola, who prefers to renew his deal on a year-by-year basis, said in the pre-match news conference on Saturday he needed more time to decide on his future.
"He knows what we think, and he'll make his decision when he is ready," Messi told Spanish television in a pitchside interview at the Nou Camp.
"We hope he stays, he is very important to us and to this club," he added.
Messi, celebrating his 200th league appearance for Barca, took his league tally this season to 27 from 23 matches - one behind top scorer Cristiano Ronaldo of Real Madrid - and to 146 since he made his debut in La Liga in October 2004.
Barcelona Vice-President Josep Maria Bartomeu said the Catalan club was not worried by Guardiola's failure to commit beyond the end of this season.
"He is an exceptional coach and he decides the timescales," Bartomeu told Spanish television. "We are at his disposition and when he wants he will speak to us.
"With him, there are no time limits. He is an exceptional person and we are counting on him."
Guardiola, who has led Barcelona to 13 trophies since taking the helm in 2008, is chasing a fourth consecutive league title.
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