The rise is likely after the NSW Independent Pricing and Regulatory Tribunal recommended a 17.5 per cent increase for ActewAGL customers in the areas of Queanbeyan, Goulburn, Yass and south-east NSW.

It’s the third straight annual increase, giving the average NSW ActewAGL residential customer a $219 increase, while small business customers face a rise of $848.

Experts believe increased exports of Australian-produced gas are causing the rising prices, which they say will hit ACT households the hardest as Canberrans turn to gas heating to beat the winter chill. Some expect domestic price levels will continue to rise to meet export price levels.

ACT Sustainable Development Minister Simon Corbell said local prices would likely rise by about $230 annually. Gas prices in the ACT are determined by the market and are not subject to a regulator.

‘‘The ACT is particularly vulnerable because of the high level of gas use in domestic households for space heating and winter heating,’’ Mr Corbell said.

‘‘The government’s position is that we first of all need to encourage households and help households to reduce their energy use and therefore their consumption and how much they need to pay for gas.’’

ACT Council of Social Service director Susan Helyar said cold winters left Canberrans vulnerable to high gas bills.

‘‘People need to use a lot of gas to keep their homes warm in winter,’’ she said.

‘‘Most households in Canberra are doing OK, they can afford an increase. But for those people who are on income support or minimum wage or are in jobs where they don’t get enough hours or work ... they stop spending money on food, on medicine or healthcare and on transport so they can keep up with their bills.

‘‘The other thing people do is not heat their houses. Those people get sick with respiratory illnesses through the winter because they are in circumstances which are unsuitable for their health.’’

Mr Corbell said schemes designed to help low-income earners with utility costs and the roll out of renewable energy projects would help Canberrans meet the cost.

Meanwhile, Origin Energy customers in south-western NSW will have a 19.4 per cent price increase in the next two years, adding $224 to household bills and $764 for small businesses.

ActewAGL’s increases were attributed to wholesale gas costs.

The regulator said the main reason for higher Origin prices was ‘‘the proposed increase in the retail and wholesale component of regulated prices’’.

In NSW, customers will pay $225 a year more on average from July 1.

The draft ruling will be confirmed in a final report due in June.

Tribunal chairman Peter Boxall blamed the increases on rising wholesale prices, saying the east-coast market was effectively connected to Asia through the Queensland LNG exports.