Multinational fossil fuel companies exploiting liquefied natural gas in Australia have built up a further $50 billion in tax credits over the past financial year, further delaying any meaningful royalty payments from the massive export sector.

A submission by the Australian Tax Office to Treasurer Scott Morrison's review of the petroleum resource rent tax, or PRRT, shows the LNG sector's combined tax credits, or "carry forward expenditure", grew to $238 billion in 2015-16, having climbed from $187 billion the previous year - or $138 million a day over 12 months.

Oil and gas market experts such as Monash University's Diane Kraal have previously warned that the industry's war chest of tax credits would shield companies like Chevron and Shell from contributing any PRRT "in her lifetime".

The PRRT is the only royalty-like payment that the big LNG projects like Gorgon, owned by Chevron, Shell and ExxonMobil, are forced to pay for the billions of dollars in Australian gas they extract and export to Asia.