"Schools are finding it difficult to cope with the mental health issues facing their children after the stresses of last year, particularly due to Covid-19," she said.
For the majority of children, lockdown and learning from home had been a good experience, giving them plenty of time with parents.
However, after they returned to school, issues such as separation anxiety, elevated anxiety, and heightened sensitivity arose in more children, she said.
"We saw an increase in anxiety-related issues, such as children melting down more in response to small setbacks."
Children had picked up on their parents' worries about Covid-19 and were triggered by warnings of potential community cases — sending them into high alert.
In general, the highest proportion of children needed support with family-related issues, and also sought help to deal with divorce, bereavement, and friendship issues.
"Often, children feel that they don't matter, that their parents don't have time or are not interested in spending quality time with them," Pierce said.
"We hear day after day that the children are wanting that connection.
"Other children may have complex mental health needs, and teachers are not trained to deal with that," Pierce said.
Last year, the Government announced that community organisations will receive $44million over four years in contracts to provide counselling to primary and secondary schools.
ChatBus would put up its hand to be included in that, but at present it was unknown how much of that money would come down south, Pierce said.
"In the meantime, we will be soldiering on and trying to deal with the increase in demand with our limited resources."
Last year, ChatBus had eight counsellors working in schools, and this would need to increase to meet the need, by at least two more counsellors and two more vehicles.
"We don't have the funding to cover that, so we are looking for corporate sponsorship to help us out.
"The other issue is finding counsellors who are trained in the specialty area of working with children."
To help cover its growing costs, ChatBus has relaunched its 1000Stars project, which allows people to sign up to be a star on www.chatbus.org.nz by contributing $20 per month.