Mr Walker, an ex-Northland Regional Councillor, said the Far North used to have a second power circuit, which would eliminate the need for shutdowns.
Top Energy was now trying to catch up on maintenance and build a second circuit, "but to have to wait until 2026 to have it sorted is ridiculous".
Meanwhile, Kaitaia Pak 'n Save, which does have backup generators, will open as usual. Kaitaia Hospital is ready for the outage with backup generators checked and tested, and a contingency plan is in place in case the switch-over doesn't work as it should.
Sunday's outage, scheduled from 8am-5pm, will replace a day-long outage which had been planned for March next year.
Work includes replacing a power pole at Umawera which has cracked.
Top Energy chief executive Russell Shaw said if the pole fell it would cut all power to Kaitaia while emergency repairs were carried out. By bringing the outage forward from March, replacing the pole could be combined with other essential work, limiting the power cut to one day.
The pole is the second structure to have failed on the Kaikohe to Kaitaia high-voltage transmission line this year. In March Top Energy had to replace a tower in the Mangamukas.