(CNN) An election official in Philadelphia on Monday said that 3,400 mail-in ballots at risk of being rejected because of incorrect information, missing dates or missing secrecy envelopes "creates a really unfair disenfranchisement to thousands of voters."
Philadelphia City Commissioners' Chairwoman Lisa Deeley initially sounded the alarm about the ballots on Saturday after the state Supreme Court earlier in the week barred local election officials from counting ballots with missing or incorrect dates on the return envelope.
Deely told "CNN This Morning" on Monday that the Pennsylvania Supreme Court decision coming down so close to Election Day does "more to reinforce people's mistrust in the process and it's a real tragedy for Pennsylvania voters."
Deeley released the affected voters' names and urged them to take immediate steps to get replacement ballots.
Officials say the numbers of at-risk ballots will grow as more are returned.
On Sunday, Allegheny County also published two lists of voters, totaling more than 1,000, who returned mail-in and absentee ballots with no date or with an incorrect date, as defined by the supreme court's order.
A highly competitive US Senate race that could decide control of the chamber is on the ballot in this key swing state, along with a closely watched contest for governor.
"I am extremely disappointed in the Pennsylvania Supreme Court's decision with regard to undated and incorrectly dated ballots," Deeley said in a Saturday statement. "Handwritten dates are not material and the lack of such a date should not be a reason to disenfranchise a voter."
Currently, more than 1,800 of the ballots flagged by Philadelphia authorities lack the required dates.
Election officials in Philadelphia say their city hall office will be open Sunday, Monday and Tuesday to help voters fix the problem.
Although election officials are working to get those whose ballots have been rejected fixed, Deeley said on Monday that a lot of the ballots were submitted weeks ago and now people "may be out of town or unavailable to come in."
Voters in Allegheny County can fix their ballots at the County Office Building in downtown Pittsburgh on Monday and Tuesday.
Pennsylvania's requirement that voters sign and provide a handwritten date on their ballot return envelope has been the subject of litigation for months. And on Friday, several Pennsylvania groups, including the state branches of the NAACP and the League of Women Voters, filed a lawsuit in federal court, challenging the state's plan to not count undated ballots.
The lawsuit calls a missing or incorrect date "a meaningless technicality" and argues that throwing out a ballot on those grounds violates federal civil rights law.