Republican presidential candidate Mitt Romney raised more than US$111 million (NZ$137m) in August, according to a statement issued by his campaign, maintaining an overwhelming cash advantage over Barack Obama.

With less than two months to go before the November 6 presidential election, Romney maintained his streak of fundraising dominance as his campaign, the Republican National Committee and state Republican parties reported that together they have about US$168.5m (NZ$207m) in cash at their disposal.

While Obama shattered every fundraising record in 2008 after becoming the first presidential candidate to opt out of a federal matching funds system, Romney has significantly outpaced the president in his bid for the White House this year.

After raising US$101m (NZ$124m) in July, Romney and the joint Victory Fund he shares with the Republican National Committee already enjoyed a US$60m (NZ$74m) cash-on-hand advantage over Obama.

The president’s campaign has also burned through money faster than the Republican candidate, spending US$58.5m (NZ$73m) in July, with about two-thirds of that going to advertising.

Republicans view the combination of Obama’s high cash burn rate and polls that show a tight race as evidence that they have withstood the advertising onslaught Obama’s campaign launched early in the year.

‘‘This race is a dead heat, even after they have spent over US$100m attacking Mitt Romney with negative ads,’’ one senior Romney adviser said Sunday.

Romney is also now free to spend the millions of dollars he raised during his primary campaign.

Legally, Romney was barred from spending money he raised before he formally accepted the Republican nomination, which he did in Tampa more than a week ago.

The day after Obama accepted his party’s nomination for president at the Democratic convention in North Carolina, the Romney campaign demonstrated it was ready to start spending some of that money in a homestretch assault on Obama.

Republicans seized on a disappointing jobs report on Friday morning, announcing they bought ad time in the key swing states Obama won in 2008 but are now in play.

Romney, on the air in the key states of Iowa, Virginia, Colorado, Florida, Nevada, New Hampshire, Ohio and North Carolina, was set to expand his advertising to Wisconsin on Monday.

‘‘What we very deliberately did, we held our powder and we knew these jobs numbers were going to be a big moment,’’ said one Romney adviser. ‘‘And we loaded up to come back on Friday, and we’ve gone up in a big way.’’

While Romney spent much of the summer fundraising, senior adviser Kevin Madden indicated that the Republican candidate would shift his focus to spending time with voters down the homestretch.

‘‘We’ll continue to do some fundraising throughout this month, but I think we’re in that critical phase where we’re trying to put our emphasis on voter contact and having the governor do more retail campaigning,’’ Madden said.

- Reuters