Two witnesses before the Select Committee inquiry into fuel pricing on Tuesday suggested concessions may be needed, given the high cost of establishing new, or renovating older, petrol stations.

The inquiry is investigating options the territory government could pursue to cut retail petrol prices, amid pressure to act on the ACT's comparatively high prices.

The head of the ACT branch of the Automotive Trade Association, Michael Burke, put the long-term decline of many independent retailers down to the growth of Coles and Woolworths-linked outlets.

Mr Burke said the growth of the supermarkets into the fuel retail sector had also seen the end of many independent mechanics and auto-shops that were once common alongside the bowsers.

But he said the deeper problem for the entire automotive industry was the rising cost of territory government rates, making it harder for existing firms and less competitive for new entrants to set up shop.

Mr Burke also said one long-term independent fuel retailer, who had since sold his Canberra outlets, had told him the outlets made more money from selling cans of Coca Cola than petrol.

He said it was the up-selling of grocery products and food and drinks that made the businesses viable, and that aspect was what had attracted the supermarkets, rather than fuel.

Similarly, a fuel price data company director and owner of independent stations, Nic Moulis, said while he shied away from the word, "concessions" may need to be considered if the government wanted more independent outlets.

Mr Moulis also gave the committee data, not yet public, showing the two major retailers often priced above the average ACT unleaded petrol price by up to four cents a litre last year.

He said the data showed Costco was about 20 cents lower than the average, while Metro averaged about 13 cents a litre cheaper.