Communities in parts of the Coromandel Peninsula remain cut off from work, school and lifeline services, including doctors and birthing units, due to highway closures.

Three weeks on from Cyclone Gabrielle, the vital State Highway 25 has suffered further damage between Opoutere and Hikuwai following heavy rain on Sunday night.

A pregnant woman, one week overdue with her first baby, faces a three-hour journey on back roads when she goes into labour, instead of a 45-minute drive. And 80 students remain unable to get to school in Whangamatā.

The under slip at that section of SH25 became worse and the road was closed again on Wednesday morning, but it temporarily reopened in the evening, although only for light vehicles.

It is expected to be closed again from 9am today. Waka Kotahi says this is subject to change and may close at any point without warning.

"I've heard some people describe it like Pac-Man ate a hole out of the road," Waka Kotahi Waikato system manager Cara Lauder told Checkpoint.

The road could be closed for weeks, not months like State Highway 25A, she says.

'It's been a bit stressful obviously'

Leilani Brown lives in Whenuakite, about 20 minutes from Tairua, and being one week overdue, she could go into labour at any moment.

"It's been a bit stressful obviously, we've had to keep an eye on the road status pages ... but things change everyday," Leilani told Checkpoint.

"Our birthing plan so far has been to give birth in Thames, at the birthing centre over there."

Leilani would usually travel on SH25A to get to Thames.

"We're looking at a pretty long travel time now, it's gone from 45 minutes, to at least a couple of hours, probably two to three."

If the roads were cut off but the weather remained fine, in an emergency Leilani says she could still get access to a Westpac helicopter if needed.

If something like another cyclone was to hit, things would be different, she says.

"The road kind of constantly floods so my midwife might not even be able to come see me."

She's contemplating renting accommodation on the coast while waiting but says this would not be subsidised.

"It's a pretty sad situation. Our midwives in the area are amazing, they do such a good job and they really take good care of everyone and same with the local healthcare providers, but it's kind of not unique to this area either."

A larger issue around propping up the healthcare system is needed, she says.

'We have a number of anxious parents and whānau out there'

Whangamatā Area School principal Alistair Luke says the school has a little more than 80 students based on the Hikuwai, Tairua side of the hill.

Unable to make the trip to school, most of those students are back to learning remotely - something they are used to doing now, Alistair says.

Whangamatā Area School principal Alistair Luke. Photo: RNZ / Tom Taylor.

A select number are attending a satellite programme based at Tairua Primary School.

"We are fortunate in that two of our staff also live on that side of the hill, so they've been able to get over to Tairua School and at least provide some face-to-face learning."

Although, Alistair says some subjects are unable to be taught remotely and NCEA students are facing assessments as term one comes to an end.

The current road access does not really help the situation, he says.

"One of the challenges for us is that one of the vehicles that travels over the hill in normal times is a 70-seater bus, so a very large vehicle of course."

A fleet of mini vans might be used to travel across when the road reopened to light vehicles, he says.

"We have a number of anxious parents and whānau out there who are always weighing up the potential risks of making a journey into school and what they might look like at the end of the day."

'We understand how frustrating it is'

An image of what the washout on SH25 initially looked like. Photo: Supplied / Thames-Coromandel District Council.

Cara says she will speak to the contractors this morning to see whether SH25 could open at times that would work for school trips.

The road will close again from 9am today to allow repair work to continue unhindered by traffic

It will reopen for an hour around lunchtime to give drivers a short window to get through.

Cara says contractors have prioritised increasing the width and length of the cut into the bank to help safeguard the access track on Wednesday.

"Arborists have removed vegetation between the edge of the cut face and the start of the pine plantation.

"We want to keep traffic as far away from the underslip as possible and ensure it's safe."

Convoys were allowed through for short periods on Wednesday to help relieve some pressure on the community, but contractors needed to keep the road shut for the majority of the day to ensure they got as much work done as possible.

"The underslip is unstable and we appreciate everyone's patience with this evolving situation. We understand how frustrating it is.''

"We're working as fast as possible to give road users a safe way through here."

Geotech investigations continue today to help with a plan for a permanent fix for the section of the highway that has fallen away.

-RNZ.