The silver fern flag with black, white and blue has come out on top in the first flag referendum.

The flag held a narrow lead in voting when preliminary results were revealed on Friday.

In the official result announced this afternoon, which included all late and overseas votes, the Electoral Commission confirmed it as the winner.

The flag will now go head-to-head with the existing flag in a second referendum in March, which will decide whether New Zealand changes its flag for the first time in more than 100 years.

Both silver fern flags were designed by Kyle Lockwood, a New Zealander living in Melbourne.