Helen Clark doco to be released this year

A feature documentary covering Helen Clark's behind-the-scenes battle to become UN Secretary-General is on the way.

Award-winning filmmaker Gaylene Preston is working on the documentary, My Year with Helen, which will be launched at film festivals in New Zealand later this year.

The doco will show the struggles the former head of the UN's Development Programme - and former New Zealand Prime Minister - faced as she implemented her programme of reform and ran for the top leadership position.

"I have wanted to make a Helen Clark documentary for many years," Ms Preston wrote on her website.

"Helen is a formidable woman and leader, and I'm honoured she's given my team access to tell this story."

Ms Preston's most recent project was the television series on the Christchurch earthquakes, Hope and Wire.