The Scottish government is to boost the incomes of the country’s poorest families by offering them £10 a week for every child in addition to child benefit payments.

Aileen Campbell, the communities secretary, said the new benefit, the Scottish Child Payment, would “tackle child poverty head on” by mitigating many of the worst effects of the UK government’s cuts in social security payments.

“Scotland is facing a spike in child poverty as a result of welfare cuts imposed by the UK government,” Campbell told MSPs on Wednesday. “We will not stand by and simply watch that happen.”

Scotland’s government has been under intense pressure from anti-poverty campaigners and Scottish Labour to use its recently devolved powers to introduce new benefits or top-up existing welfare payments. The Scottish government has a legal duty to abolish child poverty by 2030.

Labour and campaign groups had suggested an across the board top-up to child benefit of £5 or £10 a child a week, a measure Scottish ministers had resisted as it was not aimed at those in need.

The new Scottish Child Payment will be limited to poor families eligible for Scotland’s Best Start grant covering maternity and children’s early years. But parents will need to apply for the payment as they will not receive it automatically.

The benefit will first be paid out by the new government agency Social Security Scotland to families with children aged six or under by early 2021. It will then be extended to all under-16s by the end of 2023. Based on a take-up rate of 83%, the Scottish government estimated the benefit would cost £180m.

Campbell said about 410,000 children would be covered by the time it was fully implemented, helping a third of the country’s under-16s. It would lift about 30,000 children out of relative poverty (a measure which excludes housing costs) by 2024, and reach 80% of all children in poverty.

Unlike universal credit payments overseen in Scotland by the UK government, there is to be no cap on the number of eligible children in each family. Universal credit and tax credits only offer payments for the two children, although the UK-wide child benefits system has no limit to eligible children per household.

Child benefit payments are £20.70 for the first child and £13.70 for each further child – payments which will not be reduced as a result of the new Scottish benefit.

The measures were universally welcomed by anti-poverty campaigners and Naomi Eisenstadt, the first minister’s former adviser on poverty. “It’s great to see the Scottish government taking such ambitious and direct action to shift the curve on child poverty,” she said.

John Dickie, director of the Child Poverty Action Group Scotland, said: “Today’s announcement is a landmark recognition of the role the Scottish social security system can play in ending child poverty.

“It’s now vital that the UK government follows suit and starts to use its powers in an equally positive way and scraps the universal credit two-child limit and the UK benefit freeze, so that government at every level works together to protect children from poverty.”