The release of a heavily anticipated amphibious bus has been delayed after the $1.6 million vehicle broke down on its second trial run.

The Dutch-made "Amfibus" ran into problems with its suspension as soon as it entered the River Clyde, west Scotland, halting the planned voyage between the towns of Renfrew and Yoker.

Despite the hiccup, operator Stagecoach has vowed to get the 50-seat vehicle back up and running in the hope it will replace the struggling local ferry service.