As Beacon Hill lawmakers try to rewrite their annual budget plan from scratch to account for a massive drop-off in tax revenues after the coronavirus shutdown, cities and towns are being warned not to expect a promised boost to schools.

The Massachusetts Department of Revenue's Division of Local Services issued a bulletin to cities and towns telling them to expect level-funding through at least the end of August. Fiscal year 2021 was supposed to be the start of a new $1.4 billion dollar investment in K-12 schools through the Student Opportunity Act signed by Gov. Charlie Baker last November, but the coronavirus economy means delaying that promise to cities and towns.

Without the annual budget in place, districts were told by state officials to expect the same funding as fiscal 2020 with the first payment available to them July 1.

"If at that time the state budget is not final, the August payment will be made using the same methodology and will be payable on August 31st," wrote Division of Local Services Senior Deputy Commissioner Sean Cronin.

"We will re-evaluate our methodology as the FY2021 legislative process unfolds," Cronin added.

The education law, the most significant accomplishment of the legislature's 2019-2020 session, provides for $1.4 million in Chapter 70 local school aid over seven years, $90 million for increased special education funding and $10 million for an educational innovation fund.

"Not having this additional funding is a recipe for disaster at this point," Marie-Frances Rivera, president of the Massachusetts Budget and Policy Center, told WGBH News.

"It's essentially $300 million that districts across the commonwealth" will lose, Rivera said, referring to the amount of money in the governor's pre-COVID budget for the Student Opportunity Act in fiscal 2021. That will affect mainly gateway cities who serve the most kids of color and low income kids and English language learners, she added.

"Those districts were expecting this infusion of cash, which they're not going to get," said Rivera.