Waioeka Gorge is set to open tomorrow morning as long as nothing untoward happens overnight, the New Zealand Transport Agency says.

NZTA Bay of Plenty state highway manager Brett Gliddon said it planned to open a single-lane temporary diversion route by 9am tomorrow, as long as a geological safety assessment tomorrow confirmed that the slope had not moved overnight.

"We're very conscious that people are eager to get through, and we're on the verge of opening the temporary diversion, although this will depend on conditions being favourable in the morning and the hillside being assessed as safe and stable.

"We are itching to get the road open, but safety is our top concern.''