(VOA) - The Trump administration issued a memo Tuesday offering federal government workers a financial incentive to leave their posts by the end of September.

The resignation program is part of the administration’s efforts to shrink the federal workforce.

An email to many of the 2 million federal workers said they could remain on the government payroll until Sept. 30, the end of the government’s fiscal year, and could have their work duties reduced or eliminated in the interim.

Those workers would also be exempt from a Trump mandate that employees need to return to working in their offices full time.

Employees have until Feb. 6 to accept the offer, and were directed to do so with an email reply with the word “resign.”

The potential impact of the program on tax-payer services was not clear.

“While a few agencies and even branches of the military are likely to see increases in the size of their workforce, the majority of federal agencies are likely to be downsized through restructurings, realignments, and reductions in force,” the memo said.

People working in immigration, national security and for the Postal Service were not part of the offer.

The memo also said the “federal workforce should be comprised of employees who are reliable, loyal, trustworthy, and who strive for excellence in their daily work.”

Unions representing federal employees criticized the administration’s move.

The National Treasury Employees Union, which represents about 150,000 federal workers, told its members the resignation memo “is designed to entice or scare you into resigning" and said "we strongly urge you not to resign in response.”

Everett Kelley, head of the American Federation of Government Employees union that includes some VOA employees, said in a statement that the offer “should not be viewed as voluntary” and that the administration’s actions show its goal is “to turn the federal government into a toxic environment where workers cannot stay even if they want to.”

Some information for this story was provided by The Associated Press and Reuters