KUALA LUMPUR, Oct 9 — Putrajaya’s refusal to reveal the details of Datuk Seri Najib Razak, his wife and delegation's 14-day trip to Europe in August suggests the prime minister’s entourage may have misused the government’s official jet to go on “vacation”, a DAP lawmaker claimed today.

Seremban MP Anthony Loke demanded that the government prove that this was not the case, saying Malaysian taxpayers deserve to know how their money is being spent.

"The main question that needs to be answered by Datuk Seri Najib Razak is whether the taxpayers need to bear the expenses for his private vacation as well as his delegation.

"If it involved public funds, then the people have the right to know the details of the cost involved and it is fair to get questioned," Loke told reporters at the Parliament lobby.

On August 13, the Asia Sentinel portal reported that Najib and his wife Datin Seri Rosmah Mansor and their delegation "went on holiday, with no public record of where he might have gone".

The report at the time identified the plane as an unidentified privately-owned aircraft.

In a written reply to Loke, Minister in the Prime Minister's Department Datuk Seri Shahidan Kassim acknowledged the trip but said it was for an official visit to discuss the solution to the MH17 tragedy, which was shot down over Ukrainian airspace in July.

"The plane used by the prime minister was the government official jet, which was used for the prime minister's official purposes.

"The costs involved during the flight were appropriate according to its service," he said, without giving the list of passengers and a detailed cost involved.

According to media reports however, Najib only had one official function during that period, which was on August 1 in Amsterdam.

Yesterday, Loke had also demanded for a breakdown of Rosmah's travel expenses, and questioned why these were kept “secret” when they were paid for using public funds.

Shahidan had said Putrajaya does not disclose separately the cost of Rosmah's foreign trips as she travels as part of an official entourage.