Power availability in both states was threatened on Monday after wholesale electricity prices spiked, triggering a $300/MWh price cap.
As a result, some generator companies pulled back from the market forcing the Australian Energy Market Operator to intervene.
AEMO is continuing to closely monitor electricity supply reserve conditions in Queensland and NSW and across the National Energy Market.
"It is possible that other states may also reach the (wholesale) threshold in the near term," the AEMO said late on Monday night.
"Supply reserve shortfalls are currently forecast in Queensland and NSW in the coming days.
"However, this may change with the administered price caps in other states."
On Monday, the AEMO warned of possible power outages for Queensland's southeast and east coast between 5.30pm and 8pm before successfully directing electricity generators to supply enough power to meet demand.
Residents were told to turn down their heaters and switch off household appliances to conserve power.
AEMO also ordered generators to supply enough electricity in NSW to meet demand gaps, amid fears of load-shedding.
Outages at coal-fired power plants, at the same time as household heating is in high demand, are putting pressure on the electricity system.
Federal minister Bill Shorten said the power situation on Australia's east coast was "not good."
"The problem we have got right now is because of the very cold weather," he told Nine Network on Tuesday.
"You need what's called dispatchable power. That's power that you don't need ... but when it's really cold, that's when you need it."
Powerlink Queensland, the government-owned entity that owns and operates the state's transmission network, told Seven Network demand was high due to thecold snap.
"Our median demand forecast was about 7500 MW but we cracked 8000 MW, so about seven to eight per cent above what we expected," CEO Paul Simshauser said of Monday's events.
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