Farmers are slating immigration changes as pointless fiddling.

The changes mean immigrants will only have to earn 85 percent of the average wage to stay in the country for longer than three years.

Federated Farmers immigration spokesperson Chris Lewis said most migrant farm workers earn less than that.

"With a maximum of three one-year visas, it makes farmers think should we put any energy, any time into training these employees if they're going to stay for such a short term."

He said with the number of jobs going in the sector, farmers have no choice but to employ immigrants.

"When all the hard-working Kiwis have great jobs out there and there's more jobs available than hard-working Kiwis to work in them, it leaves it us no choice but to employ immigrants."