The Minster of Energy calls for more cuts in petrol prices?

The Minister of Energy Mr. Brownlee has called for cuts in petrol and diesel prices, on Monday Dec. 29 (The NZ Herald) and again Monday Jan. 5 (The Press),
It has been the norm that government officials come out to call for cuts in the prices of petrol and diesel and sometimes they go further to call for an inquiry to investigate petrol pricing in New Zealand. On the face of it, it seems a good policy that government acts as a watchdog to protect NZ customers from over-pricing. My question is that why does the Government, who is entrusted by the nation and have the legal authority to act against such improprieties, should use such a piecemeal approach to solve a problem that has been persistent for many years and have cost tax payers and the nation so dearly? The reason for that is very simple; our government has no system upon which to find out what is a fair price for petrol and regulate the market accordingly. The only system in place is the monitoring done by (MED) which is only indicative and has no compliance effect.
I am against strict regulation of the market or the prices because it is not practical and does not work, but I have called for regulatory guidelines that will at least keep the prices floating within reasonable limits and hence ensure a minimum safeguards against over-pricing. Without such guidelines government officials will continue to make calls of this kind and oil companies will always answer back to defend their position. The truth is that government argument (although correct in principle) is not based on solid evidence supported by facts and figures but based only on market indications and comparisons that can not make a very strong case for action, hence such calls will not give tangible results.