The smell has become common since the volcano erupted at 11.50pm on August 6 with residents as far as Blenheim noticing it.
The Horizon Regional Council today received "multiple complaints" about the smell being back and some residents said the sulphur had become an irritant.
Council emergency manager Shane Bayley said the smell was the result of wind drift from the mountain and was not a cause for concern.
"Our air quality monitoring sites in Taumarunui and Taihape are not showing any elevated presence of fine air particles.
"However, our team will be keeping an eye on the situation and will alert the public if this situation changes."
If the sulphur was affecting people's respiratory system, eyes or skin, MidCentral Health recommended people stay indoors with all the doors and windows closed, a council spokeswoman said.
Mt Tongariro has kept quiet in the past week, and seismic activity was low overnight.
But GNS vulcanologist Brad Scott said the volcano was degassing, producing a lot of gas and steam.
"It's putting out about 2000 tonnes of sulphur dioxide and 4000 tonnes of carbon dioxide per day. That's what people are detecting and smelling."
Scott said there were three possible scenarios for the volcano, with the most likely being no further eruptions in the next week.
The second most-likely scenario was that there may be a similar eruption to what occurred on August 6.
Scott said the least-likely scenario was that a larger eruption would occur.
Emergency services, DOC, Civil Defence, New Zealand Transport Agency and district health boards met on Friday to discuss an evacuation plan should the volcano erupt again.
Families living closest to Mt Tongariro have an action plan to refer to.
Conservation Minister Kate Wilkinson and Taupo MP Louise Upton met with iwi, the community and tourism industry leaders at Tongariro National Park today.
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