Hundreds of farms have been hit by the Christchurch earthquake and water problems may lie hidden underground.
Agriculture Minister David Carter said initial concerns had been about animal welfare.
"We're past that first stage, we now know that everything's getting adequate amounts of stock water and every cow in the
district is being milked," Carter said.
"The next stage is to assess the more difficult unforeseen damage, particularly in wells, submerged pumps and the network of irrigation that exists around the farm.
"If there is damage it becomes quite a major and urgent issue because all of these dairy farms are in a very summer drought-prone area," Carter said.
Phil Journeaux from the Ministry of Agriculture and Forestry (MAF) oversees the Government's response to disasters affecting the rural sector.
Journeaux said about 400 farms had been affected in some way by the earthquake and 150 seriously.
Agencies were working to determine the scale of the problem. "The picture's slowly getting clearer but it could be a week or so before we get a particularly accurate picture," Journeaux said.
A co-ordinator had been appointed to lead a Regional Rural Recovery Group, which was made up of a number of agencies including Federated Farmers, Fonterra and MAF.
BNZ head of agribusiness Tony Arthur said there had been growth in dairying and water was critical along the east coast as it headed into summer.
There was not a lot of irrigation taking place and it was not until systems were pressurised that issues below the soil would be understood.
Farmers would work quickly through the irrigation infrastructure.
"I don't anticipate us getting to summer and all of a sudden somebody flicks a switch and the problems are spotted, they'll be working on that right now," Arthur said.
Federated Farmers will hold a meeting for farmers today at Darfield High School, where issues to be discussed will include insurance, irrigation and managing stress.
National president Don Nicolson said it would be a chance "for people to have a say, have a bit of a social time, get together. I know how this helps, having been through the '84 flood in Invercargill."
