A new memo from the Democratic National Committee panel that handles delegate selection for the presidential nomination warns that states that hastily change the “first determining step” of their own process could be subject to penalties – including a 50% reduction in delegates – if they hold primaries after a June cut-off date.

The memo also says the panel is looking at ways to adjust how delegates are selected in response to the coronavirus pandemic.

Three states will hold primaries on Tuesday. A fourth, Ohio, postponed its vote on Monday, due to Covid-19 and its drastic effect on public life. Louisiana, Kentucky, Georgia and Maryland have also postponed their votes.

As in virtually every part of US society, election officials at every level have been discussing ways to safely administer elections without spreading the coronavirus.

The new DNC memo, obtained by the Guardian, was sent to members of the rules and bylaws committee on Wednesday night.

“We are working with state parties that need to make adjustments as needed to their delegate selection processes so they can continue without major interruptions,” wrote James Roosevelt and Lorraine Miller, the co-chairs of the rules and bylaws committee, in the memo.

“The regulations allow technical changes to be approved by the co-chairs.”

A number of states have taken dramatic steps to prevent spreading the coronavirus. Late on Monday night, Ohio’s governor, Mike DeWine, announced that his administration would order polling stations closed because of the “health emergency”.

“Several states have taken steps to change the date of their first determining step,” the DNC memo said.

It continued: “The Delegate Selection Rules provide that each state’s first determining step must take place by 9 June. If a state violates the rule on timing, or any other rule, they could be subject to penalties as prescribed in Rule 21, including at least a 50% reduction in delegates, which will need to be reviewed by the RBC.

“The deadline to elect convention participants is 20 June, so state parties should have plenty of time to elect their delegates, alternates and standing committee members.”

The committee also advised state parties “to follow the recommendations of local health officials and prioritize health and safety of all individuals. We acknowledge the situation is very different in every state and want to give state parties flexibility to adjust their plans to address their own situations and local guidance.”

When Louisiana moved its primary, the DNC issued a similar warning.

“We will continue to work with every state party as they adjust their delegate selection plans around coronavirus,” the DNC said then, adding a similar warning about the 9 June deadline.