Mid-sized business sentiment is being lifted by rising sales and production in the lead up to Christmas.

Accounting software company MYOB's latest survey shows more than three quarters believe the economy will improve in the next 12 months.

That is the highest level of confidence in three years for firms with 20 to 500 workers and turnover of more than $5 million.

MYOB spokesperson Anna-Louise Hoffmann said almost two thirds said revenue is up on a year ago, showing customer demand is returning.

"Most businesses, I think it was more than eight in 10, have reported that they've got more work or sales lined up in the pipeline for the next couple of months than they'd usually expect, which is really encouraging.

"What is also even more encouraging is that for about a third of these businesses, more than 60 percent of their sales or pipelined work is coming from new customers so that will also be helping to boost confidence and the outlook somewhat as well."

Hoffmann said mid-sized firms have more resources than small businesses, so they have withstood the economic downturn better.

"These are businesses equipped with more financial capital and human resource than our local small businesses. So, because of this they tend to be in a better position to invest in changes or improvements in their business, spend on things like innovation and therefore adapt faster when these challenges occur.

"It's certainly unusual to see this strong performance given what we've been hearing around market conditions this year but it's definitely not a like for like comparison with smaller enterprises for some of those reasons."