The image shows the bill featuring Tubman, slightly smiling, in a dark coat with a wide collar and a white scarf. That design was available as of 2016, according to the newspaper.
Mnuchin said during a congressional hearing that the 2020 design deadline set by the Obama administration was impossible due to new security features that would have to be considered.
Monica Crowley, a spokeswoman for Mnuchin, told The Times that the release into circulation of the new $20 note remained on schedule with the Bureau of Engraving and Printing’s original timeline of 2030.
“The scheduled release (printing) of the $20 bill is on a timetable consistent with the previous administration,” she said in a statement.
Bureau of Engraving and Printing Director Len Olijar said that the government had not "scrapped" any earlier design and that all options remained on the table.
He said the design published by the newspaper was not a new $20 note because it lacked the new security features that the government plans to include.
"There is nothing about that illustration that even begins to meet technical requirements for the next family of notes," Olijar said in his statement.
Critics have disputed that the wait for the bill that would be the first to feature an African American has to do with the intensive currency-making process. Instead, members of Congress and citizens have suggested that President Donald Trump's previous statements about changing the bill being a result of "pure political correctness" and his admiration for Jackson as the source of the delay.
Sen. Ron Wyden, D-Oregon, told The Associated Press, "Rather than technical delays, it appears the administration simply does not want to see an African American woman placed on our currency. Congress needs answers about how far along the redesign was before Secretary Mnuchin blocked it."
Officials from the bureau contend that the design delays have no political influence. Mnuchin and officials at the department's bureau rejected the assertion from Wyden and others.
"As secretary, my first responsibility is to ensure all security and anti-counterfeiting measures are properly taken in accordance with BEP's mandates," Mnuchin said in a statement. "The suggestion that this process is being stalled is completely erroneous."
After the image was revealed Friday, the public took to Twitter to offer their opinions on the delay and the design.
The Associated Press contributed to this story.