The Broads Authority said problems on the Reedham, Somerleyton, Trowse and Oulton Broad bridges had caused difficulties for boat users.
But Network Rail said every effort was being made to improve the ageing bridges' reliability.
According to a report from the Broads Authority, construction work on the Oulton bridge that was scheduled to last two weeks ended up lasting 162 days, causing restricted opening times.
The Trowse bridge was hit by a power surge which knocked out its electrics, resulting in a 100-day closure.
Repair work was slowed down because the computer system that controlled the bridge was obsolete and irreparable, the authority said.
The organisation also accused Network Rail of being "unwilling" to swing the Somerleyton bridge when temperatures on the bridge reach 28-29 degrees.
A spokesman for Network Rail said: "We understand the frustrations felt by the Broads Authority and boat users by the recent problems we've had with our swing bridges and we are doing all we can to improve their reliability.
"These are complex, ageing and rare structures and, as such, have been difficult to overhaul and upgrade and we ask boaters to bear with us while we carry out our essential maintenance programme."