Police are investigating the poaching of steers from a paddock off Heads Rd.
The crime has also attracted the interest of the Ministry of Primary Industries, which is warning the public about the dangers of home killed meat.
Heads and guts were all that remained of four steers, while another three needed to be put down after sustaining serious injuries during the illegal hunt on Monday night.
The seven cattle were part of a herd of 26 belonging to farmer Blair Kerwin, who uses the paddocks between Heads Rd and Puriri St as a finishing block for the cattle he raises on his Okoia farm.
They were to be his main source of income for the year, at $1600 to $1700 each, when they were sent to the works in the coming weeks.
Sergeant Greg Hemingway said the police were keen to speak to anyone who heard or saw anything suspicious taking place about 11.30pm on Monday in the vicinity of Matipo and Rogers streets. It is believed the poachers left the area via Matipo St.
Mr Hemingway can be contacted at the Whanganui police station on 06-349 0600.
He said anyone who knew of people trying to sell large quantities of beef should also give the police a call.
"I think there is an ongoing issue around poaching and beehives being stolen, so it's a good reminder to members of the public to give police a call on 111 if they encounter this kind of activity," said Mr Hemingway. "There's also the concern about whether the meat's been stored properly and if it's safe to eat."
Meanwhile, the Ministry of Primary Industries has contacted Mr Kerwin to let him know the black market for beef was a problem it was trying to combat.
A spokesperson told the Chronicle cattle had been stolen recently from farms in a number of central North Island locations including Whanganui, Taranaki, Taihape and the Rangitikei.
"There is concern the stolen cattle could end up as illegal home kill meat sales. There are numerous health risks associated with these sorts of purchases because unlike regulated meat, which is purchased from a butcher, it has not been subject to strict hygiene and inspection controls.
"The penalties if convicted under the Animal Products Act 1999 for breaches involving homekill can be significant. For a body corporate this may be a fine of up to $500,000 or for an individual, a term of imprisonment of up two years and a fine of up to $100,000.
"We encourage members of the public to call 0800 693 721 if they have any information or see any suspicious activity involving the slaughtering or processing of animals or selling of homekill."
Mr Kerwin is offering a $500 reward for the conviction of those involved and anyone with information can call 027-496 4327.