Australian pie maker Mrs Mac's has been warned by the Commerce Commission after testing found its meat pies did not have as much meat in them as their packaging claimed.

The Commission investigated after The Press newspaper in Christchurch published its own findings that the meat content in Mrs Mac's and Big Ben pies was below what was claimed on packaging.

The packaging of Mrs Mac's pies state that the meat content of the filling is 31%. The Commission's testing found that eight of the ten pies sampled had less than 31% meat in their filling. The meat content ranged from 24.3% to 34.1%. The testing found the average meat content in the filling of Mrs Mac's pies was 27.26%.

The testing of Big Ben pies, produced by New Zealand manufacturer Allied Foods, found that the average meat content of 24.1% was close to the 25% meat content claimed on packaging. The Commission has advised Allied Foods of its concern that one of the pies tested had a meat content of only 21.8%.

Commerce Commission Director of Fair Trading Deborah Battell said that the content of meat pies was of concern to New Zealand consumers.

"Kiwis love their meat pies, and they want to know that they are getting what they are promised," said Ms Battell.

"Misleading claims about meat content can give pie makers a competitive advantage because some consumers will shop around, so it's important that claims about meat content are accurate."

Ms Battell noted that at up to $3.20 a pie, Mrs Mac's are at the higher end of the meat pie price range.

The Commission's testing on the two brands of pies was conducted by AgriQuality, Auckland. Ten pies from each brand were tested. The Commission's test results are separate from, and have not relied upon, the testing conducted by The Press.