The UK gas crisis has claimed another two energy companies, bringing the total number of households that have lost their supplier this year to almost 2m.

The regulator, Ofgem, confirmed that Avro Energy, which supplied gas and electricity to about 580,000 households, and Green, which had more than 250,000 customers, have dropped out of the energy market.

The collapses bring the number of suppliers that have buckled under the pressure of record gas market prices to seven in just over six weeks. Their customers encompassed 1.5m households. In total nine suppliers have gone bust this year, affecting about 1.9m homes.

Neil Lawrence, a director at Ofgem, said it was “a worrying time for many people” but urged households to wait for a new supplier to be appointed before trying to switch energy deals.

Newcastle-based supplier Green collapsed just days after admitting it would struggle to survive the winter if the government refused to provide any support to smaller energy suppliers.

Green’s chief executive, Peter McGirr, told the Guardian there would be a “tsunami of more [collapses] to come” because small suppliers do not have deep enough pockets to weather the surge in costs without passing them on to their customers.

“We’re an independent company,” he said. “It’s hard to access finance and nothing has been done to help.”

He added that the crisis talks held last weekend by the business secretary, Kwasi Kwarteng, had failed to include the smaller suppliers that are most vulnerable to the energy market shock and said his company’s calls for help from the industry regulator had “fallen on deaf ears”.

Green once made a healthy profit margin of about 3.5% on its energy deals, McGirr said, but all suppliers in the market are currently making a net loss because costs have climbed quicker than the regulator’s cap on energy tariff prices.

Gillian Cooper, the head of energy at Citizens Advice, said the latest failures would “add to people’s worries at what’s already an extremely unsettling time”.

“Supplier collapses and rocketing energy prices, combined with the looming cut to Universal Credit, are creating huge amounts of uncertainty for millions of people,” she said.