Since he took office seven months ago, Donald Trump has played a lot of golf. So much, in fact, that the US Secret Service has reportedly forked out $US60,000 ($A75,600) in golf buggy rentals for agents to keep up with the First Golfer.

It’s a hefty sum for leisure time on the links, but the golf buggy fees are just a tiny part of the ballooning budget that has pushed the Secret Service to the financial brink.

According to the organisation’s director Randolph ‘Tex’ Alles, more than 1000 agents have already maxed out on pay − for the entire year.

While the department was under fiscal pressure even before Mr Trump became President, the blowout is being blamed in large part because of the sheer size of the First Family.

“The President has a large family, and our responsibility is required in law,” Mr Alles told newspaper USA Today.

“I can’t change that. I have no flexibility.”

Under Mr Trump, said Mr Alles, 42 people have protection, including 18 family members.

The Obama administration had 31.

In March, the Secret Service requested an extra $US60 million ($A76 million) in funding for the next year, because of the complicated lifestyle of the Trump family.

Now, the money crunch is biting so hard that Mr Alles told USA Today the Secret Service will not even be able to pay agents for hundreds of hours of work already done.

With agents in tow, Mr Trump has left the White House to travel nearly every weekend. He has visited his Mar-a-Lago estate in Florida seven times and hit the links at his New Jersey golf club five times.

The Secret Service has to keep up a regular security infrastructure at each location. During the President’s tee times, the golf clubs also still need to allow access for members and paying guests.

Each Mar-a-Lago homecoming adds $US3 million ($A3.78 million) to the Secret Service budget, estimated USA Today.

Last week, Mr Trump also dropped by his duplex in Trump Tower in New York, where First Lady Melania Trump and son Barron lived until June, with their own security detail.

According to The New York Times, the Secret Service had a command centre in Trump Tower but were forced to move it to a caravan outside the building because of a failed lease negotiation.

Bloomberg.com keeps a running internet tally of how much New York has spent “protecting this guy”, with the total − hovering around $US26 million ($A32.8 million) − updated in real time.

Source: Bloomberg

Adding to the overall bill is that Mr Trump’s five adult children and eight grandchildren also need to be kept safe at their homes and on international business trips, including those to promote Trump-branded properties.

There are reports nearly $US100,000 ($A126,000) was spent by the Secret Service for hotel rooms when Eric Trump visited Uruguay earlier this year for work.

In February, he and brother Donald Jr took a full security detail when they opened a new Trump hotel in Canada, and when they opened a Trump golf club in Dubai.

When Ivanka Trump and her husband Jared Kushner went skiing in Aspen, Colorado, in March, agents went along for the ride.

Youngest daughter Tiffany Trump holidayed in Europe not just with her boyfriend, but with Secret Service staff.

With his ranks thinning because of constant travel and overtime, Mr Alles has asked for the combined salary and overtime cap for agents to be boosted from $US160,000 to $US187,000 ($A201,000 to $A236,000).

In September, nearly 150 foreign heads of state are due to meet in New York for the United Nations General Assembly.

Finding enough security to go around for the talk fest will be tough, Mr Alles said.

“Normally we are not this tapped out.”