Federated Farmers Wanganui president Brian Doughty said urban residents were becoming more educated about acceptable standards of farm animal welfare.
"It's no good sitting back and complaining about town people coming out and not knowing anything," he said. "People see what they see. They will be making those judgment calls and, I think, rightly so.
"We have to continue to tell our industry that they need to be up to the mark, and if they're not, people driving around from anywhere are within their rights to make that call.
"Whether it's a right or wrong [call] doesn't matter. If they make the call, some judgments can actually be made about it."
Social media played a part in holding farmers to account, he said. "If someone sees something going on on a farm that they don't think is right, it could be on Facebook or Twitter or wherever within seconds. Farmers need to be aware of that."
Nationwide, MPI received 2947 complaints about animal welfare between 2010 and 2014.
Commercial farms accounted for 1852 of the complaints, while lifestyle blocks accounted for 785 complaints - an over-representation of complaints, according to MPI.
"Last year between MPI and the SPCA we responded to almost 500 complaints involving lifestyle blocks," MPI compliance operations manager Gary Orr said.
Mr Orr believed many complaints stemmed from a lack of knowledge in basic farming practices. Just under 100 complaints nationwide resulted in prosecutions, with thousands more resulting in verbal advice, education letters, written warnings, and other "investigation outcomes".
MPI presently found about 27 per cent of complaints were unsubstantiated on inspection.
With the increasing mobility of New Zealand's population in the pursuit of recreational activities, greater numbers of urban Kiwis are exploring rural New Zealand. "Unfortunately, a lot of these visitors apply their pet standards to production animals and they can be a little surprised to learn it is not illegal to allow sheep to give birth in the rain or a chicken farmer doesn't have to muster his free range chickens into the shed during a storm."
The Government had just funded another six full-time animal welfare inspector.