The partial sale of Meridian Energy began overnight, as the Government looks to sell 49% of the state-owned power company.
The share offer began at 12.01am on Sunday.
Forty five percent of the Meridian Energy share offer has already been allocated to stock brokers after they were invited to make bids before the public offering begins.
The Government says it's committed to keeping 85 to 90% ownership of Meridian Energy in this country once the listing is completed.
Once shares are allocated, investors can pay for them over two instalments.
The first instalment is fixed at $1 per share and is due halfway through October while remaining payments are due in a year and a half.
People can apply for shares online, by completing a paper application form or through a share broker.
The offer will be open for three weeks.