The Farmers' Union of Wales today warned farmers in Gwynedd to be vigilant after two suspicious fires in one week badly damaged farm buildings and equipment some 10 miles apart at Pencaenewydd and Llaniestyn on the Lleyn peninsula.
North Wales Police and the North Wales Fire and Rescue Service are investigating and the FUW urged farmers to remain vigilant and report anything suspicious.
"This is a cause for concern for a great number of farmers in the area," said FUW Gwynedd county executive officer Gwynedd Watkin.
"Farms, because of the nature of the industry, have been expanding, and there are also fewer people around in rural areas to keep an eye on what is going on," he said.
Mr Watkin said that because the farm house was often a distance from farm buildings it made them "easy targets" for anyone intent on causing damage.
He said the fires had not been confirmed as definitely deliberate, but there was nothing - such as electricity - in either of the two sheds which could have started a fire.
Mr Watkin added he was hopeful the situation could be sorted out soon. "This is a massive loss for the farmers, even though the insurance should reimburse them.
"I cannot put enough emphasis on how important it is that everyone keeps an eye out and reports anything suspicious to the police," he added.
FUW Insurance representative Irfon Hughes said the fires highlighted how important it is to keep all paper work up to date.
He said that location made it difficult for people to find their way around, and it was possible that anyone responsible would be familiar with the area.
"I've been working on the Lleyn for two years, and it has taken me that long to get to know all the little lanes in the area," he said.
He warned too that it was only a matter of chance that no livestock was lost during the recent incidents, as a shed of calves were saved just before the fire spread.