We report on a search for the charmless decays $B^{+} tophipi^{+}$ and $B^{0} tophi pi^{0}$ that are strongly suppressed in the Standard Model. The analysis is based on a data sample of $657 times 10^6$ $B bar{B}$ pairs collected at the $Upsilon(4S)$
resonance with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. We find no significant signal and set upper limits of $3.3 times 10^{-7}$ for $B^{+} to phi pi^{+}$ and $1.5 times 10^{-7}$ for $B^0 to phi pi^0$ at the 90% confidence level.
