Immediately following the disaster the company was forced to ask its four largest customers to curb their gas consumption in an effort to forestall enforced rationing.

AGL said that until the problem was resolved, it would have to source more expensive gas from Bass Strait.

"Until Santos resumes normal gas supply levels, AGL is sourcing additional higher priced gas from Bass Strait to maintain supply to the NSW gas market," said AGL managing director Greg Martin.

"These additional costs are expected to be fully recovered from industrial and commercial contract gas customers."

Gas is supplied to residential and small business customers under pricing arrangements approved by the Independent Pricing and Regulatory Tribunal, (IPART). As such, higher costs can only be passed on to these customers with approval from the regulator.

AGL said it would seek permission from IPART and the Essential Services Commission in South Australia to recoup a portion of the extra costs from residential and small business customers in NSW and South Australia.

"They are unfortunate but necessary costs as a consequence of us being able to get emergency gas supply to our customers, which is our priority right now," said Martin.

In addition AGL also has electricity retail and gas-fired generation interests in South Australia that it manages through its wholesale electricity contracts. At this stage, no adverse financial impact to these contracts is anticipated.