After an engineering assessment and load testing, the bridges were reopened at 4pm yesterday.
However, the speed limit has been lowered from 30kmh to 20kmh as an added precaution.
The bridges closed on February 8, when flows reached 1552cumecs because Meridian Energy Ltd had to release water after heavy rain in the upper catchment. Yesterday, the flow at the bridges was about 610cumecs.
During the interim, the southern bridge at the Kurow end had been reopened to local residents driving light vehicles, but only pedestrians and cyclists had been allowed across the northern bridge.
New Zealand Transport Agency area manager Colin Hey said the inspections carried out yesterday were "comprehensive safety inspections".
They did not identify any permanent damage to the two bridges.
A loose pier at the north end of the northern bridge had settled back into place, with the lower river flows sweeping shingle around it.
The load testing yesterday involved using two single-axle trucks, increasing their load and measuring deflection of the structure. The bridge passed to full class 1 standards.
That meant the bridges could be reopened for use by light and heavy vehicles.
Mr Hey thanked the community for its patience during the closure.
"We understand the hardship and inconvenience this closure has caused for local residents and businesses, but the safety of road users is our top priority and we simply could not allow traffic on to the bridges until the river receded enough to allow for the thorough inspections we carried out," he said.
Mr Hey acknowledged reopening the bridges would be "a huge relief for local residents and businesses".
Construction of new two-lane bridges, estimated to cost about $15 million, was scheduled to start next year and be completed in 2014, but that was subject to resource consents and funding being granted.
