Queen’s Road, Newark, was closed on Monday at its junction with Bargate, Northgate and Appletongate following the discovery of the hole which is estimated to be between 6ft and 10ft deep.
It extends from the centre of the road towards Morrisons carpark.
Engineers from Nottinghamshire County Council and Severn Trent Water have examined the hole but have yet to establish its cause.
The county council said the road would remain closed until at least Bank Holiday Monday.
Mr Malcolm Peet of Malcolm Peet Ltd said staff at his garage noticed the road was sinking yesterday and contacted the county council who sent repairmen out to fill the dip.
Mr Peet said when they tried to fill the dip the road fell through to reveal the cavernous hole beneath.
A spokesman for the county council said the road would remain closed while work took place to establish the cause of the collapse and repair the damage.
UNISON worker Mr Kirwan, who says he is the only local candidate within the main five parties, said he would campaign to stop fracking in the Newark area, pointing instead to solar panels as a better way to provide renewable energy.
“It’s important that people understand the repercussions of fracking, it’s a short-term energy solution, and the fact that the government are planning to buy people out in exchange for drilling under their house tells you it’s a bad idea.