National grid operator Transpower says there is enough power to see New Zealand through the current cold snap.

While the situation was "tight", Transpower said it did not anticipate disruption to the grid.

State-owned Transpower yesterday issued a CAN (customer advice notice) and sent a message to the nation's generators that more power would be required to maintain the normal buffer of 200 megawatts.

CANs were not unusual and were seen in the industry as a successful way of managing the system.

"The industry has responded to our request for additional generation to cover an anticipated increase in electricity demand this evening resulting from the cold snap around the country," Transpower general manager operations Stephen Jay said.

"The industry has responded to our request for additional generation to cover an anticipated increase in electricity demand this evening resulting from the cold snap around the country," he added.

"This has restored residual generation closer to the minimum buffer we try to keep in the system to help us maintain grid security," he said.

"The situation remains tight and we will continue to work closely with industry to ensure that generation supply meets demand tonight.

"To be clear, we do not anticipate any disruption to electricity supply for consumers," Jay said.

A CAN gives generators early notice that if the situation worsens, the country may have insufficient generation to meet demand and cover reserves for a contingent event, such as a generator failing.

It requests generators to make extra supply available and is the first in a hierarchy of communications for when the system comes under pressure.

The next step is a warning notice (WRN) which involves further requests to participants to help resolve the situation.

Third on the list is a grid emergency notice (GEN) which involves requests to major industrial customers connected directly to the national grid and distributors to take action.

Transpower chairman Keith Turner told the Herald in July that New Zealand's power generation system could do with more capacity.

Separately, outgoing Genesis chief executive Marc England said last month there was enough power to go around - for the moment at least.

"That being said, it is an issue that will grow," he said in an interview.

"As time goes on, New Zealand is going to have to make sure that it has the right market incentives to enable what we call fast-start peaking - so that it can turn on generation quickly in order to meet demand every time there is a cold evening," England said.

About 85 per cent of New Zealand's power supply came from renewable sources, with the figure expected to hit 96 per cent by 2030.

As it stands, the country's thermal generators - such as Genesis Energy, which had the coal and gas-fired Huntly Power Station - kicked in during times of high demand.