A heavy rain warning for the Bay of Plenty has now passed and the weather situation looks set to improve as the day goes on.

Overnight, the region saw heavy rain with warnings of potential surface flooding and slips possible.

"A few stations around Whakatane recorded over 90mm in the last twelve hours, and even a couple recorded over 90mm since midnight," says MetService meteorologist Alwyn Bakker.

"A thunderstorm over Whakatane from around 2am to 3am was partially responsible for the heavy rainfall."

The warning for heavy rain continues until 10am today but the weather is then expected to improve as the day goes on.

MetService has warned of potential rainfall of 80mm to 120mm with peak intensities of 20mm to 30mm, possibly more, from 8pm last night until the warning passes later this morning.

Waka Kotahi/NZTA confirms that there have been some roading issues due to the weather, but nothing of major significance and no road closures.

"In the East there were some small localised slips and flooding on SH2 through the Waimana Gorge and a tree down at the SH2/SH30 intersection at Awakeri," says a Waka Kotahi spokesperson.

"Our contractors have been out since the early hours of this morning clearing these."

The MetService is reporting that rain should ease to showers this morning and will become isolated as the day goes on.

"Remaining rain clearing by late morning, then partly cloudy," says Alwyn. "One or two showers possible late afternoon or evening."

Northerlies, turning westerly, are expected..