"This is a trend we have seen before following periods of high investment, with angels shifting their focus to follow-on deals in subsequent years," Twiss said.
"The second half of 2015 will be more telling in terms of how wider events are impacting on early-stage investing by angel networks and funds. It is likely the full year will be somewhat down on the previous year, reflecting a level of restraint driven by recent events in the wider economy."
However, he said there remained strong investor interest in New Zealand technology, particularly if it could address global opportunities.
Forty-three per cent, or $8.8 million, of the funds invested in the first half went into software and service firms. A further $3.4 million was invested in pharmaceutical and biotechnology companies.
According to the index, $9 million of the angel capital invested during the first half of the year was seed investment, while $11.1 million was start-up stage and $500,000 early expansion or expansion stage.
Seventy-seven per cent of the $20.6 million was follow-on investment. The average deal size in the six-month period was $388,000, compared with the long-term average of $480,000.
Angel Association chairman Marcel van den Assum said angel investors were coming off a previous year in which a lot of new investment had taken place.
"When economic conditions tighten, it is natural that investors will look to continue to support those companies in their portfolio which are doing well and meeting milestones," van den Assum said. "That is borne out by the higher level of follow-on investment we are seeing in the market."
He said the angel investment sector had become an important part of New Zealand's capital markets.
"Angels are a critical part of the deepening that we have seen in our early-stage capital markets over the past few years," van den Assum said.
"With the emergence of crowdfunding platforms, angels will be watching how that part of the market develops over the next few years."
