UPDATE 1-Brazil's Lula pledges to maintain fiscal policy

(Updates with quote, background)

By Todd Benson

SAO BERNARDO DO CAMPO, Brazil, Dec 14 (Reuters) - The Brazilian government will keep to a strict fiscal policy despite losing a vote in Congress on renewing a tax seen as vital to public finances, President Luiz Inacio Lula da Silva said on Friday.

"There will be no irresponsibility. We are going to maintain the primary surplus and we are going to continue with a serious fiscal policy," Lula said in a speech at a car factory near Sao Paulo.

The Senate on Thursday voted down a bill that would have extended the so-called CPMF tax in the government's biggest setback in Congress since Lula took office in 2003.

The opposition seized on public resentment to the tax, which is charged on everything from personal checks to money transfers, to derail the bill.

The tax, which expires on Dec. 31, brings in an estimated 38 billion reais ($21.5 billion) a year in revenue.

"The people who voted against it did not use good sense," Lula said.

Finance Minister Guido Mantega has sought to dispel concerns that the government might seek to fill the budget gap by relaxing fiscal policy. The government will unveil a series of measures next week to make up for the shortfall, Mantega said on Thursday.

Some economists said Brazil may now take longer to reach an investment-grade credit rating, which would allow the government to borrow at lower interest rates and attract a wider pool of investors. (Reporting by Todd Benson; Writing by Angus MacSwan; Editing by James Dalgleish)