The companies are the latest providers to go bust following the recent increase in wholesale gas prices.
However, both Avro Energy and Green have reassured their customers and have said that they will continue to receive energy until a new supplier is appointed.
Retailers could potentially be hit with rising costs to their gas and electricity bills.
Ofgem’s chief executive Jonathan Brearley said: “We do expect a large number of customers to be affected. We’ve already seen hundreds of thousands of customers affected, that may well go well above that. It’s very hard for me to put a figure on it.
“It’s not unusual for suppliers to go out of the market, I think what is different this time is that dramatic change in the costs that those suppliers are facing.
“We do expect more (suppliers) not to be able to face the circumstance we’re in, but it’s genuinely hard to say more than that, party because that means predicting what may happen to the gap price.”
Once an energy firm collapses, customers are automatically switched to a tariff provided by a new supplier. Customers will continue to receive gas or electricity despite the companies going bust. Ofgem will automatically move your account to a new supplier.
The increase of wholesale gas prices recently has meant that a number of small companies have collapsed including, People’s Energy, Utility Point, PfP Energy and MoneyPlus Energy.
The coronavirus pandemic is one of many reasons why gas prices have increased, with the demand for global gas having risen.
Ben Ford, Retail Services Director at PayPoint said: “Despite recent developments relating to gas prices, we want to assure PayPoint retailers that the service we provide will remain unaffected. In cases where a customer’s energy provider is no longer able to operate, Ofgem has secure measures in place to ensure gas and electricity supply will continue uninterrupted by moving them to an alternative supplier. We’ll continue to monitor the situation and welcome any retailers with questions or concerns to get in touch with us directly.”