Replacement of the old wooden Kurow bridges is scheduled to begin in March, but authorities are confident the recent rain has not badly affected them.
The 132-year-old twin bridges have been plagued by closures during the past few years.
The NZ Transport Agency has committed $17 million in funding towards their replacements, but work was not expected to be completed until the end of next year.
An agency spokesman confirmed the work was due to start in March, and consultants had regularly inspected the bridges following last week's rain.
Environment Canterbury duty flood controller Chris Fauth said an extra 100mm of rain fell in the Waitaki catchment at the weekend, adding to the 1 metre that had fallen in the past fortnight.
Mr Fauth said the river was flowing about 1100 cubic metres a second; if it reached more than 1300 cumecs, the Kurow bridges could be closed.
"We've spoken to consultants for NZTA over the last day or so, and they were reasonably pleased with how they've held up. They don't think they will need to close the bridges at this stage."
The flows were expected to remain high even if there was no rain over the next three days, as a lot of water needed to go through the system.
"The catchments are very large, there is a bit of a lag in the system. Fortunately, it didn't rain as much over the weekend as forecast," Mr Fauth said.
"Once again, we ask campers to get to high ground and make sure they're aware the river's flow could change very rapidly," he said.
MetService forecaster Daniel Corbett said it was unlikely that there was going to be any major rainfall in the Waitaki system during the next week, but a low-pressure weather system moving onshore could lead to spotty showers in Timaru.
- The Timaru Herald