Some farmers in the lower North Island have had no option but to sell their stock, including pregnant ewes, after floodwaters washed away feed and destroyed pasture.
Last week's extreme flooding left the Whanganui, Taranaki, Manawatu and Rangitikei regions with a medium scale adverse event declared, and a clean up bill estimated by Horizons regional council to be more than $120 million.
Many people living in rural communities, including the Waitotara Valley, remain isolated because of slips.
Federated Farmers Whanganui president Brian Doughty said people living in cut-off areas have all been visited and will continue to get food and medical supplies via helicopter drops.
He said the Whanganui region hadn't had any rain over the weekend, and people were cleaning up their farms in whatever way they could.
"For those that have got diggers, they've been trying to get their tracks and fences and temporary fences back up again.
"For those who haven't got diggers, there's not a lot that they can actually do; the slips are still reasonably wet and still fairly free moving if you start to shift them.
"The unfortunate thing is that it's scanning time for the ewes, so some of those people will be putting scanning on hold.
"I've heard of others that are seriously affected by erosion and they're actually having to sell in-lamb ewes because they've lost 20 percent of their feed. How they get them out of those valleys is going to be a challenge as well."
Mr Doughty also warned farmers about scammers after the flood.
He said people had been calling farmers offering them money from a relief fund which didn't exist, and asking for their bank account details.