WELLINGTON (Reuters) -The New Zealand government said on Wednesday that it would financially support investment by the country's energy companies in critical electricity infrastructure.

The government holds a 51% stake in the formerly state-owned generators Genesis Energy, Mercury and Meridian. Energy ( MDDNF ) prices have risen in New Zealand as supply has tightened, putting energy generators in the spotlight.  

Finance Minister Nicola Willis said in a statement that she had written to the three electricity generators to say that the government is prepared to support capital funding requests for strategic and commercially rational investments that support energy security.

"Reliable and affordable energy is key to New Zealand's prosperity," she said.

An independent review of the country's electricity system found that the companies have faced constraints in their ability to invest in larger generation projects, because of a perception that the government would not provide equity injections to support those investments.

Willis added the government was committed to retaining its 51% stake in the companies.

The government also announced a procurement plan for a liquefied natural gas import facility and will strengthen the Electricity Authority to make it a "more powerful, decisive regulator."