New Zealand has voted to keep its current flag in a referendum.

Prime Minister John Key first suggested revamping the 112-year-old flag which features a Union Jack in the corner as it represented the country's colonial era and it looked too similar to Australia's.

Two referendum have been held in 2015 and 2016 - the first to decide on a preferred alternative from a shortlist of four, and second to choose between that alternative and the current flag.

Preliminary results show more than two million were votes cast in total.

One million votes were for the current flag and just over 915,000 were for Kyle Lockwood’s, who designed the proposed change of flag.

The official result for the second referendum on the flag will be declared on Wednesday March 30.