Federal tax authorities will extend a limited amnesty program for taxpayers who have undeclared income on foreign accounts to Oct. 15 from Sept. 23, according to a government official familiar with the matter.

The Internal Revenue Service amnesty program began in March after Swiss bank UBS AG turned over the names of some account holders as part of a $780 million criminal settlement with the U.S. government.

An extension was granted after tax professionals pleaded for more time to help taxpayers enter the program. More than 3,000 taxpayers have come forward, compared with less than 100 for all of last year.

After months of tortuous negotiations that involved the Swiss government and challenged the country’s tradition of banking secrecy, UBS agreed in August to disclose the names of 4,450 American holders of secret accounts at UBS.

The IRS amnesty program could result in account holders paying large monetary penalties but avoiding criminal charges.