The average loss rate across countries participating in the international survey, from the most recently available period (2018/2019), was 16.7 per cent.
Findings from a similar survey in the US found the winter loss rate over the 2019/2020 period was 22.2 per cent.
As in past years, New Zealand beekeepers reported that the primary reasons for overwintering losses in 2020 were queen bee problems, suspected varroa infestation, suspected starvation and wasp attacks.
Foster said there had been promising advances in both the area of varroa management and in the use of biocontrols to deal with wasps.
However, dealing with queen problems was more complex and the subject of research both within New Zealand and internationally.
"Ongoing research is a vital part of reducing colony loss, but also beekeepers know that their everyday management of these threats is key to hive health," Foster said.
"The survey is a really valuable tool in measuring how we are doing, and where more efforts are needed."
The New Zealand Colony Loss Survey also unearthed the experiences of Kiwi beekeepers.
The 2020 survey asked questions on beekeepers' views on aspects of their work, their overall experience and how they accessed beekeeping information.
The findings showed that the economics of beekeeping was the biggest challenge for many and that most beekeepers learnt their skills through a beginner's course or from a mentor.
Apiculture New Zealand CE Karin Kos said these findings supported what she'd been hearing from beekeepers.
"It is a difficult time to be a commercial beekeeper, especially for those not involved in mānuka production."
In terms of training, she said more and more beekeepers were looking to professional qualifications and advanced courses to learn their skills.
"Our industry is seeing the value of having well-trained workers which is why we are seeing a huge increase of interest in programmes like our Apprenticeship in Apiculture scheme."
This scheme currently had over 200 participants who were training while working in the beekeeping industry, up from 75 people in early 2020.
The New Zealand Colony Loss Survey is based on an online survey of beekeepers and is part of an international effort involving more than 35 countries.
It is produced each year by Manaaki Whenua Landcare Research for the Ministry for Primary Industries.
Find out more about the survey here.