Farmers must soon submit forms to the Northern Ireland Environment Agency (NIEA) showing the movement of organic manures off their farm.
Records for 2019 must be submitted online by 31 January 2020, the Ulster Farmers' Union (UFU) said.
If the records are not submitted, the slurry export will not be included when calculating a farm's nitrogen loading.
Farmers could then find themselves in breach of the rules and they could also face a higher risk of inspection.
If farmers are not already using DAERA online services, they will need to register with the government gateway to obtain access to the online export forms.
Records sent to NIEA must cover the date moved, type of livestock manure, quantity (tonnes or cubic metres) and the transporter's name and address.
The importers name and farm business ID is now also a requirement. Exports of livestock manure (including poultry litter and slurry) to the Republic of Ireland are regulated by animal by-product legislation. This involves applying for authorisation to export.
UFU environment chairman, Wilbert Mayne said: “Many farmers recognise that importing slurry, chicken litter or manure is a useful source of nutrients on a farm and can displace artificial fertilisers.
“It is important that these farmers supply their farm business numbers to the exporters of organic manures, to ensure all are compliant with the Nutrients Action Programme rules.
“The UFU accept that the regulations are complex and onerous, but farmers have a legal obligation to comply regardless of whether they are claiming area-based payments.
“Failure to do so could result in penalties,” said Mr Mayne.