The Australian Energy Market Operator has temporarily suspended the spot market in NSW, Queensland, South Australia, Tasmania and Victoria - the states involved in the national electricity market.

AEMO says it has become impossible to continue operating the spot market while ensuring a secure and reliable supply of electricity for consumers in line with the rules.

WHAT ACTION IS BEING TAKEN?

The market operator will apply a set price for the five states in the NEM, compensating the generators who bid into the market during the suspension price period.

It followed AEMO being forced to direct five gigawatts of generation through direct intervention on Tuesday and finding it was no longer able to operate the spot market or power system in this way.

The market will resume operating normally as soon as is practical.

AEMO has assured the federal government there will be enough power to avoid load-shedding or blackouts.

WHAT CAUSED THE PROBLEM?

* A large number of power plants are out of action for planned maintenance

* Planned transmission outages

* Periods of low wind and solar output

* Around 3000 megawatts of coal-fired generation out of action through unplanned events

* The early onset of winter, increasing demand for electricity and gas.

Australian Associated Press