A 24-hour national strike by Royal Mail workers on Friday (29 June) means copies of Farmers Weekly magazine may arrive later than normal.
The strike, by members of the Commercial Workers Union, could also have implications for farmers using the mail to apply for cattle passports.
The British Cattle Movement Service has stated it will be sympathetic when it comes to applications arriving a day later than expected due to postal problems.
But the NFU is reminding farmers that it remains their responsibility to make sure that documents arrive on time.
It is therefore essential that proof of posting is obtained from the Post Office when posting applications.
BCMS has also warned that the strike could contribute to a slight delay in producers receiving cheque book style passports through the post.