Earthquake-hit Canterbury farmers are being told they can turn their irrigation systems back on.

Farmers were advised to leave their pumps off immediately following the quake to allow aquifers that may have moved to settle.

Irrigation New Zealand chief executive Graeme Sutton now the worst of the aftershocks look to be over, farmers should run tests as soon as they can.

"It’s very difficult to distinguish between what might be a leak and what might just be natural fluctuations, but we’re urging farmers to do those tests now rather than wait until irrigation season.”

Mr Sutton says damage to pumps isn’t as bad as first feared.

“It’s probably not as big an issue as we thought it would have been, but those closer to the faultline will have greater problems."

Mr Sutton says farmers should have an electrician and pumping engineer on hand when they start their pumps.

Any farmers who need further help can call Irrigation New Zealand on 03 379 3820.