OTTAWA — A second veteran Liberal MP in as many days has announced he'll resign early, opening his riding to a potential late-summer byelection.

Jim Peterson, a former trade minister, will vacate his Toronto seat of Willowdale on July 12 instead of waiting until the next federal election.

Peterson, who had earlier indicated he would not seek re-election, made the announcement today in the Commons.

The 65-year-old noted that fixed-election-date legislation passed this spring could delay the next general vote until October 2009.

The Liberals have several candidates from last year's crowded leadership race sitting unelected on the sidelines, and the party would like to get them into Parliament as soon as possible.

Former Ontario NDP premier Bob Rae holds the Liberal nomination in Graham's riding of Toronto Centre, while another Martha Hall Findlay has the nomination in Willowdale.

Both ridings are considered safe Liberal seats.

Federal rules state the prime minister must call byelections in vacant ridings within six months of the vacancy.