Scottish Labour said the policy would only involve additional funding for councils already running the clubs.
A Scottish Labour government would provide two free weeks of holiday clubs for children during the summer holidays.
The policy is aimed at easing the pressure on working families and ensuring parents are still able to work during the summer and would cover all primary school age children.
The announcement comes ahead of a visit by party leader Anas Sarwar to a youth club in Lanarkshire.
At his party’s campaign conference earlier this month, First Minister and SNP leader John Swinney promised tapered support for childcare which would see the poorest parents pay nothing, 52 weeks a year and up to the age of 12.
The £500 million project will require expansions to the existing system, while Scottish Labour has said its plans would merely require an increase in funding for councils already delivering the clubs.
Ahead of the visit on Tuesday, Mr Sarwar said: “Scotland needs change after 20 years of SNP government and parents need a break from John Swinney’s failures draining their hard-earned cash.
“For too many working parents, the summer holidays are not a break. They are a source of stress, worry and extra cost.
“The SNP has made promise after promise on childcare, but too many families are still left to patch things together and pay the price.
“I’m standing to fix the mess, get the basics right, and build a better future for Scotland.
“A Scottish Labour government will provide two weeks of fully funded holiday clubs for primary school aged children, helping parents with costs and making sure children have somewhere safe, supportive and fun to go over the summer.
“This is practical help for working families and part of our plan to build a childcare system that gives parents more choice and works around the reality of family life.”
Scottish Green co-leader Gillian Mackay said any pledge to expand childcare was “welcome”, but questioned the ambition of the Labour pledge.
“The Scottish Greens would roll out 1,140 hours of funded childcare to all two-year-olds in Scotland and provide 570 hours of funded childcare to every child from six months to two years old,” she added.
“High quality, affordable childcare is an investment in parents as well as children. Expanding it is one of the most crucial steps we can take to tackle inequality.
“Every vote for the Scottish Greens is a vote to support children and their families and to build a greener and kinder future where every child can thrive.”
Scottish Liberal Democrat economy spokesperson Jamie Greene MSP said: “Having kids is an expensive business.
“There are too many postcode lotteries under the SNP, with lots of families denied the critical support they need.
“Scottish Labour could have made this less of an abstract election promise and delivered something concrete by making it a key budget negotiation.
“Instead, they walked away with nothing, in stark contrast to my budget deal.
“By backing the Scottish Liberal Democrats on your peach, regional ballot paper in May, you can vote for a realistic plan that will give parents access to flexible, affordable and fair childcare.”
Mairi McAllan, SNP candidate for Clydesdale, said: “Our transformational childcare package will be a complete game-changer for families across Scotland.
“Year-round childcare support, 52 weeks a year, for every child from nine months old, right until they leave primary school – that’s what an SNP government on Scotland’s side will deliver.
“We are offering 52 weeks support, Labour are offering two. While Anas Sarwar plays catch-up, our offer to every single Scottish family is childcare which fits around families needs – parents’ work doesn’t stop during the summer holidays so neither will our provision of childcare.
“John Swinney’s strong leadership is firmly focused on the priorities of the people of Scotland and our landmark childcare policy is a clear demonstration of the type of Scotland we will build – that’s what’s on the ballot in May.”
