An error by the Prime Minister's Office has resulted in a federal byelection in the former riding of late NDP leader Jack Layton being pushed back a week to March 19.

The embarrassing gaffe was corrected less than 24 hours after Prime Minister Stephen Harper issued a news release saying voters would get a chance to fill the downtown Toronto seat on March 12.

A spokeswoman in the PMO says the new date was the result of an administrative error.

In layman's terms, a press release went out to the public announcing the byelection before cabinet had technically approved the date.

The oversight is likely to cause more irritation in NDP ranks, since it pushes the highly symbolic byelection even closer to the party's March 24 leadership weekend, when a permanent leader to replace Layton will be chosen.

Some New Democrats were already upset that Harper did not allow the party to chose its new leader before the Toronto-Danforth byelection vote was held.

Layton died of cancer last summer and the New Democrats have picked law professor Craig Scott to carry their banner in his former riding.

The Conservatives have nominated communications specialist Andrew Keyes to run for them and the Liberals have yet to choose a candidate.

Adriana Mugnatto-Hamu, who ran for the Green Party in the 2011 federal election, was nominated by the party Sunday to run again in Toronto-Danforth.

The riding, located east of downtown Toronto, is a diverse section of the city that was known as a Liberal bastion until Layton's 2004 election. At one point in the late 1970s it was represented by then-NDP MP Bob Rae, who is now interim Liberal leader.

There are eight candidates vying to replace Layton as leader, including former party president Brian Topp, Toronto MP Peggy Nash and former deputy leader Thomas Mulcair.

Layton died only a few months after he led New Democrats to official Opposition status in the House of Commons.