In a letter to Kate Forbes, the organisations warn that action to increase the Scottish Child Payment is needed urgently to protect families from a "perfect storm of financial uncertainty".
They call on her to make the necessary financial commitment to double the £10-per-week-per-child benefit for low-income families, and warn that "amid a rising tide of poverty, children living in poverty right now simply cannot wait".
The Scottish Government has already pledged to increase the payment to £20 within the lifetime of the parliament and First Minister Nicola Sturgeon said in September that it will happen "sooner rather than later".
Signatories to the letter include Barnardo's Scotland, Oxfam Scotland, the Moderator of the General Assembly of the Church of Scotland, the STUC and the Children and Young People's Commissioner.
John Dickie, director of the Child Poverty Action Group (CPAG) in Scotland, a member of the End Child Poverty coalition in Scotland which co-ordinated the letter, said: "Doubling the Scottish Child Payment is the single most impactful thing the Scottish Government can do right now to protect families and give Scotland a chance to meet our child poverty targets.
"Families really cannot wait any longer for this financial support."
The letter has also been signed by teaching unions including the Educational Institute of Scotland, the Royal College of Paediatrics and Child Health, women's organisations, disability organisations and community groups from across Scotland.
In it they say that the UK Government's removal of the £20 Universal Credit uplift, the increase in energy prices and the broader rise in the cost of living are increasing financial insecurity for those who have been hardest hit by the pandemic, particularly women, single parents, disabled people and those from black and minority ethnic communities.
They warn that many more families are now at risk of poverty.
The Scottish Child Payment is currently paid at £10 per week for each child under six in families in receipt of a qualifying benefit such as Universal Credit.
Bruce Adamson, Scotland's Children and Young People's Commissioner, who has signed the letter, said: "Poverty was the biggest human rights issue facing children before the pandemic, now it is worse. Children have the right to an adequate standard of living and to benefit from social security.
"The government has a duty to use its resources to the maximum extent possible and that includes doubling the Scottish Child Payment now."
A Scottish Government spokeswoman said: "The Scottish Child Payment is the most ambitious child poverty reduction measure anywhere in the UK. It is a unique benefit which has already provided the families of around 108,000 children aged under six with £10-a-week payments.
"We remain committed to doubling the Scottish Child Payment to £20, four times what was originally asked for by poverty campaigners, and will deliver this as early as possible. We will outline our plans during the budget process.
"In addition we are investing £77 million a year in annual £520 bridging payments, so supporting a further 150,000 children and young people from low-income families ahead of rolling out the Scottish Child Payment to under-16s by the end of 2022."