Parks charity GreenSpace wrote to the education department on behalf of its members and other green space bodies involved in the GreenLINK coalition after ministers said the £235m project, launched in 2008, was being scrapped.
Sarah Cox, policy officer for the charity, said many local authorities wanted to try and influence recent policies and decisions due in this month's spending review.
In his letter, GreenSpace chief executive Paul Bramhill said Playbuilder helped where play provision had failed to meet the needs of local children. "These schemes have redefined the social position of children, placing them at the heart of their communities rather than the marginalised edges," he wrote. "They have redefined their lifestyles, replacing obesity and inertia with activity and fitness."
The axe fell on Playbuilder in August, when education secretary Michael Gove froze grants to 132 councils for up to 1,300 schemes. Only those where construction had already started were to be allowed.
Anne Jackson, a children's director from the department, said difficult choices had to be made to bring down the budget deficit. Play was one of many programmes that would have to contribute to these savings, she wrote to Bramhill.
"We have been working with local authorities to identify savings on play budgets, with the aim of helping projects to progress where affordable. Local authorities will be notified of their revised play capital allocations in due course."
But GreenSpace business development manager David Tibbatts said: "With so much already ploughed in and gained, the hasty abandonment of Playbuilder risks seeing two years of investment totally wasted.
"There seems to be a culture that we all have to share the pain of the cuts equally, but is that good enough? The truth is not all public spending is equal. Some spending brings a greater social return on investment than others."
GreenLINK coalition members signing up to the letter included the Federation of City Farms & Community Gardens and the Association of Garden Trusts.
GreenSpace said it now wanted to work with local authorities and groups such as the Association of Play Industries to forge a more unified campaign.