Mr Birch said slumps on Tinui Valley Rd have been aggravated by continual high river levels.
Maintaining safe access for light vehicles was also proving difficult on Tanawa and Te Mai roads, and Ngahape Rd beyond Syndicate Rd, he said.
Major repairs will be tendered as a package after specific design work for each site is carried out, he said. This, coupled with an ongoing wet winter, meant long-term repairs were not likely to be under way before November.
Emergency response and routine clean-up operations in the Masterton district in July cost $60,000 and Mr Birch said the cost of permanent repairs would be about $500,000.
The council would approach NZTA to fund part of that cost but it would have to come up with about half itself, he said.
The council's reserve fund for rural road repairs had a budget of $250,000 a year.
Carterton District Council roading manager Walter Middelberg said he told yesterday's council meeting that storm damage this winter had done about $300,000 worth of damage to the district's roads. That compared with about $110,000 last year.
Mr Middelberg said the council would approach NZTA to help fund the repairs, while the rest of that cost would come out of council reserve funds. He was unsure how much had been budgeted for that.
Most of the damage in the Carterton district, including slips and road dropouts, was on hill roads towards the coast.
Due to the weather, the council was working on just keeping those roads open rather than trying to repair them now, he said.
Mr Middelberg did not want to comment on the potential for the situation to worsen, given that Met Service's Wairarapa forecast for the next six days predicts rain on four of them: "We'll just have to wait and see. We've got no control over the weather."
South Wairarapa District Council group manager infrastructure and services Mark Allingham said there were slips or dropouts on hill roads in the South Wairarapa district, which has the biggest land area of the three councils.
But damage was on a par with previous years.
"Three years ago, we had one really big slip, last year we had a whole pile of small slips and this year we've got a lot of little drops all over the place," Mr Allingham said.
He couldn't put a figure on the cost of repairs and there were no plans to approach NZTA for emergency funding.
He said the annual cost of repairing South Wairarapa's rural roads after storm damage had varied from nothing to $800,000.