The land in question comprises two plots in the Khao Son 2 area, one spanning 31 rai and the other 15 rai. The two tracts are determined to have encroached on national forest land.
The Ratchaburi MP was also found to own a 691-rai plot in the Khao Son 1 area reserved for poor farmers under the land reform policy.
Ms Pareena operates chicken farms in both the Khao Son 1 and 2 areas, located in tambon Rang Bua, Chom Bueng district.
Deputy Minister of Agriculture and Cooperatives Thamanat Prompow said on Monday that chickens at the farms were removed prior to the authorities' inspection of the two areas on Sunday.
Ms Pareena is accused of occupying more of the designated land than legally permitted. An occupant is allowed to use no more than 50 rai of the reform land for agriculture. The land can be passed on to heirs but cannot be sold.
Capt Thamanat said Ms Pareena's land in Khao Son 1 will be seized for suspected violation of the Land Reform for Agriculture Act.
However, the authorities cannot press criminal charges against Ms Pareena for breaching the act because the 10-year statute of limitations has lapsed. The RFD handed the land to Alro as part of the reform zone in 1993.
Capt Thamanat said Ms Pareena has the right to appeal the ministry's order to seize the land for re-allocation to eligible farmers.
"If Ms Pareena can prove she is a farmer qualified to occupy the land, up to 50 rai will be returned to her," the deputy minister said.
"The same standard applies to everyone," he added.
Meanwhile, Mr Atthaphon said Sunday's inspection of the Khao Son 1 and 2 areas was conducted with the court-approved search warrants.
The RFD is focusing its attention on the Khao Son 2 zone, alleging Ms Pareena is illegally occupying and making use of the forestland. He said the department has lodged a legal complaint against the PPRP MP.
Ms Pareena took to social media on Monday to announce the legal action she is facing is the least of her concerns and she had consulted with lawyers and intends to fight the case in court.
Also on Monday, Deputy Prime Minister Prawit Wongsuwon, who is also chief strategist of the PPRP, said the party would not protect Ms Pareena if she was found to be in the wrong.