Small businesses may feel a pinch today as workers juggle childcare duties on top of their everyday jobs.

School is out for thousands of children as most schools will close during an historic teacher strike.

It comes after hopes for last-minute talks to avert the teachers' mega-strike crumbled.

The Ministry of Education has posted a list of 1229 of the 2409 state and integrated schools with union members that will close.

However, many more schools are also expected to do so but have not notified the ministry, as they are not required to do so.

BusinessNZ Chief Executive Kirk Hope said the mega-strike would affect dozens of businesses across the country, particularly small businesses.

If two or three workers were absent from a workplace of five or 10 it had a pretty big impact on business, he said.

"You'd expect large business to be able to cope but this is a pretty widespread strike, probably one of the most significant strikes we have had for some time in New Zealand.

"So there will be an impact on a wide range of businesses that's for sure."

Their advice had been to communicate to staff members about what the options were, he said.

Some workers may be able to bring children into work, while others might be better taking a day off, he said.

"The useful thing is that this has been well signalled."

While it was a "shame" that it could not be settled, the reality was people had known for some time if their school was closing, he said.

Auckland Business Chamber chief executive Michael Barnett agreed that the strike had been well signposted, allowing businesses and parents alike to plan ahead.

Businesses were taking greater responsibility to provide greater flexibility for employees, he said.

Auckland Council general manager libraries and information Mirla Edmundson welcomed parents and children to spend the time off visiting the city's libraries.

"Libraries are an excellent place for parents and children to spend time with each other and take advantage of the great range of books on offer," Edmundson said.

"While we do not have anything particular planned for tomorrow's teacher strike, we welcome parents bringing in their children to our libraries tomorrow."

Stanmore Bay Pool and Leisure Centre, Allan Brewster Leisure Centre and West Wave Pool and Leisure Centre all had holiday programmes on offer for children tomorrow.