NSW plane search called off for the night

A search for a missing ultralight plane and its sole occupant in northeastern NSW has been called off for the night after crews identified possible crash sites.

Police and SES officers spent Wednesday scouring bushland after pilot Ian Sinnott failed to reach his destination the previous day.

The 72-year-old took off from Murwillumbah Airport about 10am Tuesday and the alarm was raised when a member of the public spotted the plane in trouble near Limpinwood.

The search was called off as light faded on Wednesday and will begin again with an additional helicopter - bringing the total number to nine - on Thursday, an Australian Maritime Safety Authority spokesman told AAP.

Crews have not been able to find any crash site despite receiving several reports of broken trees in the region.

Chief Inspector Luke Arthurs said the plane's bright green colour was making the operation harder.

"The bush ... is very green at the moment with the recent rains so it is making it difficult," he told reporters.

Mr Sinnott's wife was devastated, he added.

"She's actually out assisting with the search trying to locate her husband," Insp Arthurs said.

Muddy terrain was also hampering rescue crews.

Friends and family of Mr Sinnott have described him as a "great aviator" with at least three decades' experience.

The search zone was refined to an area of about 185 sq km on Wednesday.