"It is certainly worth watching because it is dry in some areas - drier than this time of year should be in terms of soil moisture levels," he said.
El Nino, if it arrives, did not automatically mean wet conditions in the west and dry weather in the east would eventuate, he said.
Chris Allen, who has a sheep and beef farm in mid-Canterbury, said the dry weather was already having an impact.
"It's pretty dry and that's starting to show up in the shallow aquifers and some of the river flow levels, so irrigation over the last week has had to fire up," he said.
But no one is raising the spectre of drought just yet, said Allen, who is Federated Farmers' spokesman for water and the environment.
"Farmers are thinking about it," Allen said. "It will take two or three weeks for them to start making decisions," he said.