Hawke's Bay highway travellers are being advised to expect some slight delays as contractors respond to the summertime road condition known as "bleeding seal".
"Or in layman's terms, 'sticky tar," New Zealand Transport Agency's Napier journey manager Oliver Postings said.
Recent rising day and night-time temperatures had caused some stretches of roading to show signs of rising, soft tar, especially on the state highways.
"It is particularly noticeable on SH5 between Napier and Taupo and SH2 to Gisborne."
Contractors were out on the highways last week and were likely to be out again this week with temperatures of 26C expected across parts of the region today and 24C tomorrow.
There is likely to be a brief rain break on Friday and into Saturday, but then clearing as warming weather returns.
Mr Postings said contractors would be out laying surface chip over affected areas to soak up the rising bitumen where required.
"This happens every year and we are always monitoring it to ensure that we can respond appropriately."
As well as watching for bitumen, work crews are continuing seal preparation at various sites across the region's highways for a resurfacing programme which is set to get under way in late January.
Delays would be minimal however.
"The longest sites being several between Paki Paki and Waipawa on SH2, several sites around the Nuhaka area, one long site on Links Road [SH50] and a number of consecutive sites on SH5 north of Te Pohue," Mr Postings said.
Closer to town, motorists travelling this weekend are being advised that there will be a closure of SH2 at Pandora Pond for the IronMaori Triathlon.
As in previous years there will be no vehicle access between Westshore and Napier, via Pandora Road and the Westshore Bridge, between 7pm on Friday and 4pm on Saturday.
"As usual there will be times when travel through the Prebensen Drive and Expressway Roundabout will be very slow," Mr Postings said, adding that using data from previous events travel time could be changed by up to five minutes.
"Please be patient through the roundabout and be tolerant of the cyclists and those manning the traffic management and please allow additional time if travelling to the airport for any flights."