* Parliamentary ballot follows Macron's May election win
* Majority key for Macron to carry out pro-business reforms
* Run-off round on June 18 (recasts with projections)
PARIS, June 11 (Reuters) - Emmanuel Macron's fledgling party seized a big lead in the French parliamentary election first round on Sunday, projected results polls showed, setting the president on course for a massive majority to push through his pro-business reforms.
The results, if confirmed, are another blow to the country's mainstream Socialist and conservative parties already reeling from Macron's election in May, which blew apart the left-right divide that has shaped French politics for the past century.
Pollsters said well over 30 percent of those who voted had picked Macron's party in the first round, a result which they said could deliver him as much as three quarters of lower house seats when the second round results come in next week.
Macron professes to be neither right nor left. His one-year-old Republic on the Move (LREM) party fielded more than 400 candidates, bringing together seasoned veterans and political novices including a former bullfighter, fighter pilot and ex-armed police commander.
"It's a renewal of the political class," said Jose Jeffrey, a health ministry administrator who voted LREM. "Ive known people who have been MPs for 40 years."
At the close of voting, pollster Elabe projected Macron's Republic on the Move and its centre-right Modem ally would win 32.6 percent of the first round vote.
Trailing behind, the conservative party The Republicans and their allies were forecast securing 20.9 percent support; the far-right National Front 13.1 percent; and the Socialist Party and a grouping of left-wing parties 9 percent.
Elabe projected this would translate in the second round into a massive 415-445 seats for LREM-Modem. The Republicans would become the largest opposition force with 80-100 seats, Elabe projected, with the National Front seen winning 1 to four seats and the Socialist Party and other leftists 30-40 seats.
Other polls predicted similar outcomes - results that would give France's youngest leader since Napoleon a powerful mandate with which to make good on his campaign pledges to revive France's fortunes by cleaning up politics and easing regulations that investors say hobble the euro zone's No.2 economy.
Turnout was low, interior ministry data showed.
(Additional reporting by Cecile Mantouani, Antoine Boddaert in Paris, and Gabriela Baczynska and Charlotte Steenackers in Brussels; writing by Ingrid Melander; editing by Richard Lough and David Evans)