The Prime Minister has come under fire after mistakenly telling Mike Hosking she was "pretty pleased" with gross domestic product growth having received a "hint" ahead of Thursday's official release of the second-quarter economic data.

Newstalk ZB political editor Barry Soper told Andrew Dickens a Prime Minister or politician should never comment in advance when it comes to GDP.

"In my view, the listeners this morning would have been in no doubt to what she was talking about. She should not of been confused about what she was being asked about, its difficult to accept her excuse."

LISTEN ABOVE AS BARRY SOPER SPEAKS TO ANDREW DICKENS