MEXICO CITY (Reuters) - A dinner of champagne, caviar and smoked salmon at up-market department store Harrods was how Hilda Garcia, a Mexican anti-corruption official, spent part of her $450 per day travel allowance in London last year.

A colleague, Jorge Pulido, sent to Kuala Lumpur for a conference, managed to spend more on taxis and meals out during a layover in Frankfurt than he did on his six-day hotel stay in Malaysia.

Jaime Cerdio was more austere. On a trip to Washington, he lived off $10 sandwiches and soda bought at the local Safeway and paid back almost a third of his total per diem allowance, replenishing the government's coffers with more than $1,000.

Mexico's Public Administration Ministry (SFP), charged with oversight and accountability in government, is responsible for reining in spending and tackling corruption. But it admits it has little idea how its own employees spend public money abroad, an examination by Reuters shows.

The SFP has only paper records of its employees' travel and government rules only require boarding passes and hotel receipts as verification. This means a large chunk of employees' per diem spending goes unchecked.

The ministry's finance department could not answer Reuters' questions on how many employees traveled last year, for how long and how much they spent. Instead, it handed over about 1,000 pages of paper files in cardboard boxes to review.

"We are reviewing this to make sure best practices are applied to this kind of spending," SFP head Virgilio Andrade told Reuters when asked whether officials should provide more details of how they spend government money abroad.

A new transparency law, approved last year, will mean government agencies and entities have to electronically publish their travel spending, Andrade said.

He hopes that will improve accountability since Mexicans will be able to see where government officials are traveling on official business and question travel spending.

For now, though, the government, tarred by conflict of interest scandals over home purchases by President Enrique Pena Nieto, his wife and his finance minister, has yet to introduce proposed rules to enact the transparency law and there is no date for when entities will have to make additional information - such as travel spending - public.

That has allowed Mexican government employees - even those at the SFP - to live large on foreign trips.

One SFP official, Alejandro Bonilla, in Hawaii for Trans-Pacific Partnership negotiations, enjoyed the calamari at his hotel in Kona so much he ate three rounds in 24 hours. He said his job managing the government's contracting policy unit means that he has to attend events such the TPP talks, which included two meetings in Hawaii and one in Guam last year.

EXPENSIVE

Pulido, the SFP's head of legal affairs, who spent more than $500 on two taxis and two meals in Frankfurt en route to an anti-corruption conference in Kuala Lumpur, said meals and taxis in Frankfurt are expensive and that he still did not spend more than his $450 per diem over the two days he was traveling.

In the United States, government officials are entitled to per diem allowances in limited circumstances and must provide receipts for reimbursements.

The $450 per day allowances for Mexican government workers abroad is more than the U.S. government pays in many U.S. cities but it is below the U.S. rate for some expensive foreign cities, such as London and Paris.

Per diem payments can lead to 'double dipping', for instance, if government officials also accept gifts of meals or travel, said Alexandra Wrage, founder of anti-bribery organization TRACE International in Annapolis, Maryland.

"Then the extra is cash in hand for the government official, which is pretty close to a bribe," she said.

Reuters found no evidence that any of the SFP officials accepted gifts of meals, travel or accommodation while also receiving a full per diem payment.

Andrade defended the per diem, saying that giving employees government funds upfront reinforces the idea that the trip is for official business.

Cerdio, the sandwiches-and-soda employee - who heads the transparency and accountability department - was the only one of 11 public servants who took trips between January and August last year to provide receipts and itemize all of the money that he spent from his $450-a-day-allowance.

Cerdio did not respond to requests for comment.

Garcia, the official who dined at Harrods, handed in most of her receipts.

One of her other meals was at Starbucks, she noted, and she viewed the meal at Harrods as a reward after a tough day working on an extradition process that involved multiple meetings in English discussing unfamiliar British law.

    "We don't have the luxury and privilege to eat in Harrods every day."

(Reporting by Elinor Comlay; Editing by Simon Gardner and Kieran Murray)