The state and federal governments will spend an additional $8 million on Mitchell's new bridge in Queensland's southern inland.
The existing bridge over the Maranoa River was severely damaged in last year's record flood and work is already underway on its replacement.
The federal member for Maranoa, Bruce Scott, says the extra money will be used to make the bridge higher and longer.
"Which will put it above the 2012 flood level and importantly it will be wider than the old bridge, meaning type-two road trains will be able to now, once the roadway is ... upgraded east of Mitchell, bring type-two road trains all the way through to Roma," he said.
"It is important that the new bridge is going to be well above previous, last year's flood event because it is the main access route through there right through to Darwin.
"It's a major point and if it goes out as it did last year during the floods, it's caused enormous dislocation to traffic, as well as the general public."