Staying open was not a viable option, because guests did not want to stay while the generator was operating, she said.
They were seeking about $3500 compensation for the two nights, which would cover the cost of fully booked rooms.
However they had been told by Unison no compensation would be offered.
The couple were told last month Unison wanted to carry out the work in March - in the middle of the motel's busy season, Ms Gibbison said.
They had complained through the Electricity and Gas Complaints Commission, and yesterday were waiting for an official council noise reading.
Unison spokesman Danny Gough said while he understood the couple's frustration, offering compensation would set a "dangerous precedent" for future work.
"They felt they needed to close their business - we don't necessarily agree with that decision."
Unison had done all it could to mitigate the couple's concerns by condensing all the work into two days with "staff working around the clock" to finish the job.
Editorial, p8