Data released on Thursday shows 26 per cent of children were living in relative poverty in 2019/20 – around 260,000 youngsters.
This is up from 23 per cent in 2018/19, when around 230,000 children were living in relative poverty.
Households which are in poverty under this measurement have incomes below 60 per cent of the median (middle) UK income.
The 2017 Child Poverty (Scotland) Act, which was supported by all parties at Holyrood, set targets to reduce child poverty to less than 18 per cent by 2024 and less than 10 per cent by 2030.
Campaigners said the latest data is “a source of national shame” and called for the new Scottish child payment benefit to be at least doubled.
Almost 100,000 applications were made for the £10-a-week benefit when it launched earlier this year.
Responding to these official statistics, Chris Birt, Deputy Director for Scotland of the Joseph Rowntree Foundation, said: “Today’s statistics show that even before the pandemic, an unacceptable number of people were trapped in poverty in Scotland.
“None of us want to live in a country where over one million people, including around 250,000 children, live in poverty.
“For people in poverty, returning to normal after the pandemic is not good enough.”
He added: “On the first day of the election campaign, these statistics underline the urgent need for a passionate debate about how we drive down poverty in Scotland.
“People here believe action to significantly reduce poverty is possible and are restless to see greater action from our political leaders.
“To provide a credible route to the child poverty targets they all signed up to, we will need to at least double the value of the Scottish Child Payment, support parents into good jobs and improve the quality and affordability of housing for all families in Scotland,” he said.
Mr Birt continued: “The fact that over two-thirds of children live in a household where someone is working shows that our jobs market is not providing a reliable route out of poverty for far too many people.
“The disproportionate impact of poverty on people from Black, Asian and Minority Ethnic backgrounds is shocking.
“We know the past twelve months of the pandemic have caused immense harm to the lives and livelihoods of so many in our society making it even more vital we build a recovery that is felt by everyone.”
Child Poverty Action Group director John Dickie said: “That so many more children face the daily stress of seeing their parents fret over paying bills, buying food or getting into debt should be a source of national shame.
“Behind these statistics are children whose health is being undermined, education diminished and life chances cut short.
“The good news on a day of dismaying statistics is that here in Scotland many families are now already benefiting from the Scottish Government’s new £10-a-week Scottish child payment.
“These new figures demonstrate forcefully why the payment needs to be at the very least doubled as the next vital and urgent step toward meeting the child poverty targets agreed by all the Holyrood parties.”
The SNP has been contacted for comment.