Business leaders will meet assembly government ministers later to discuss how economic activity can be sustained during the cold snap.
South Wales Chamber of Commerce says jobs and businesses are at risk.
Meanwhile, councils say grit stocks are running down quickly and they will soon have to prioritise where they treat.
Overnight temperatures plummeted to -15C (5F) in places, over 110 schools are shut and rail services hit again.
South Wales Chamber of Commerce Chief Executive David Russ said some companies were unable to function during the prolonged bad weather.
They are meeting the asembly government at 1600 GMT.
"We will use the meeting to raise our concerns that a lack of action plan to deal with the adverse weather is inflicting potentially lasting damage to the economy, with disruption to many businesses," he said.
"However, more importantly, we will be discussing solutions, and how the private sector can assist WAG in putting in place a local authority disaster plan to safeguard businesses in the region in future bouts of severe weather."
Susan Briscoe, a designer and textile artist from north Wales, said: "The problem I've got is I live outside of Wrexham . . . the roads have not been ploughed and they've not been salted either."
She said she did a lot of work around the UK but had been unable to travel.
She also said she was limited in the work she could do from home because postal services had been hit and she was not receiving delivers of supplies.
A respite from the snow is expected in parts of Wales on Tuesday but forecasters say wintry showers will continue for first Gwynedd and Conwy, and later west Wales.
In particular a new severe weather warning of snow in Pembrokeshire has been issued by the Met Office.
Grit supply dwindling
Cardiff council says it has 200 tonnes of grit supplies left and Pembrokeshire council report "significantly more" grit has been used than first thought.
"As a result, gritting of secondary and minor routes and reactive gritting requests will not be attended to except in case of emergency," said a council statement.
Steve Thomas of the Welsh Local Government Association (WLGA) told BBC Radio Wales councils were trying to help each other.
"The supply is dwindling and people are trying to stretch it out.
"Hopefully deliveries will come in in the next few days.
"I suspect people will have to look at the length of roads that they grit and prioritise.
"The problem is that it's a European-wide problem... but there is no point pretending that the stocks are not running down very quickly."
The assembly government is responsible for maintaining the motorway and trunk road network in Wales, while local authorities have responsibility for maintaining local roads.
Deputy First Minister and Transport Minister Ieuan Wyn Jones said: "We are coping as best we can in very difficult circumstances.
"We are assessing the situation on an hourly basis when snow is falling heavily and working with local authorities to try to make sure that they have sufficient supplies.
"We are expecting further supplies at the end of this week.
"Some local authorities are running lower than others and therefore we are assessing the situation across Wales to see if we can help each other."
Meanwhile on the roads, Traffic Wales said hazardous conditions are reported on various main routes including almost the whole length of the M4 in Wales.
Arriva Trains Wales says services may be delayed or cancelled on Tuesday with some trains between Swansea and Cardiff hit and an amended timetable on the Valley lines.
And flights are operating from Cardiff Airport although there are some delays and bus services are returning to normal.