U.S. Senator Ted Cruz (R-TX) speaks with reporters after the weekly party caucus luncheons at the U.S. Capitol in Washington June 23, 2015. REUTERS/Jonathan Ernst

WASHINGTON (Reuters) - Republican Senator Ted Cruz and the outside groups supporting his presidential bid have raised more than $51 million in the three months since he launched his campaign for president, according to a statement from his campaign on Sunday.

Cruz, who announced his candidacy on March 23 in a speech at the conservative school Liberty University in Lynchburg, Virginia, has raised far less in donations directly to his campaign than his supporters have collected for the four outside spending groups supporting him.

The statement said there were 175,000 individual donations to the campaign with an average contribution of $81. About $10 million came in during the second quarter of the year.

Final figures from political action committees supporting him have not been released yet but the Cruz campaign said that in June the groups announced having already brought in more than $37 million.

Last week, the campaign for Hillary Clinton, the clear front-runner in the Democratic field, announced she had raised more than $45 million since entering the race in April.

Cruz, the firebrand first-term senator from Texas, has 4 percent support in an average of polls on realclearpolitcs.com.

Cruz has been appearing at conservative cattle calls and meeting behind the scenes with wealthy Republican donors to try to build a base of supporters. Earlier this year, he courted casino magnate Sheldon Adelson, appearing at a gala in New York hosted by the billionaire and speaking at a dinner for wealthy Republican Jewish donors. There is no indication that Adelson has decided to support Cruz.

But Cruz already has gathered support from other ultra-rich backers, including the billionaire hedge fund manager Robert Mercer. Mercer and two others seeded a pack of spending groups called Keep the Promise, allowing Cruz to reveal a $31 million haul in a single week.

Cruz and his campaign team are prohibited by campaign finance laws from coordinating their campaign strategy with the outside groups but Cruz spokesman Rick Tyler has in the past announced combined fundraising figures for both Cruz's campaign and the outside groups.

(Writing by Bill Trott; Editing by Mark Trevelyan)