Bunjil farmers Kim and Kylie Lakeman are among several big Western Australian clients of Achmea Farm Insurance understood to have had their policies cancelled with short notice.
They are now scrambling to get quotes and organise insurance through another company before the winter cropping season kicks-off.
Mr Lakeman said it was a major inconvenience.
He said the local Achmea Farm Insurance broker had advised the company was cancelling their farm's insurance on January 12 and gave no reason for the decision.
"They said they would advise us by mail about the cancellation about six weeks prior to the end of the current policy period," Mr Lakeman said.
"But it is now the end of February when the policy was due for renewal and we received the notice of cancellation via email on February 5.
"We now have to find alternative insurance for the whole farm."
Mr Lakeman said they had not made any big claims on the Achmea Farm Insurance policy.
He said they had made a small claim of $285,000 (ex GST) after ex-Tropical Cyclone Seroja.
Mr Lakeman said the company had claimed their farm was remote and maybe that was the reasoning behind the policy cancellation.
"It has really inconvenienced us and it is frustrating to not have a valid reason for cancellation," he said.
"We have been with Achmea Farm Insurance for five years and liked the fact it had an association with Rabobank.
"We are now running around getting quotes and it is not easy to find a new insurer.
"We want this sorted out as soon as possible because you don't know what's around the corner."
An Achmea Farm Insurance spokeswoman said any decision made to not offer the renewal of an insurance policy was a difficult one, which was made with careful consideration.
"These decisions are driven by a number of different factors, including the need to effectively manage our risk exposure," she said.
"In instances where we are not able to offer an insurance policy renewal, we work diligently to inform our clients prior to the expiry of their policy.
"Our communications with a client impacted by a non-renewal have included phone conversations where possible and written correspondence."
Achmea Farm Insurance's website says a policy can be cancelled on any grounds set out in the Insurance Contracts Act 1984, by giving the client notice in writing.
Cancellation takes place at the time the client enters into another contract of insurance intended to replace their Achmea Farm Insurance policy, or at 4pm on the third day after delivery of a notice to the client - whichever is earlier.
It says it will refund the premium paid for the unexpired term of the policy.