The only minister in the Cabinet of Prime Minister Sergei Stanishev without an overt party affiliation, Finance Minister Plamen Oresharski until recently appeared to be also the most unshakeable. His default answer to demands for increased spending - "no" - endeared him to international financial institutions and foreign analysts, while domestically the ruling majority trumpeted him as the architect of Bulgaria’s macroeconomic stability.

Now, in the wake of the row over reported siphoning of value-added tax by criminal groups, allegedly with the help of senior National Revenue Agency (NRA) officials, his job security is at its lowest since the Cabinet took office.

For the first time, Stanishev was forced to publicly defend Oresharski, even if the manner in which he did it suggested that it was not necessary: "Enough foolishness. Minister Oresharski is one of the best [ministers] in the Cabinet." Stanishev said that Bulgaria was in a stable financial situation, proof positive of Oresharski’s good performance.

Even Milen Velchev, deputy chairperson of ruling coalition minority partner National Movement for Stability and Progress, came out to say that a Cabinet reshuffle was not "on the agenda". And that despite the fact that there is no love lost between Velchev and the man who succeeded him as finance minister.

Oresharski always had his detractors among opposition politicians, who have not forgotten the "betrayal" of the man once nominated to run for mayor of Sofia on a centre-right ticket, but Stanishev’s support and a booming economy meant his job was never in any jeopardy.

Over the past 12 months, however, his standing has been eroded by a series of events that raised questions marks about his ability to provide guidance on matters other than a flourishing budget surplus.

First came the internal Finance Ministry investigation into the former head of the National Road Infrastructure Fund (NRIF), accused of handing contracts to the company in which his brother was a director. The report, released in May 2008, famously concluded that "based on the results of the investigation, one can conclude that [NRIF head] Vesselin Georgiev could have found himself in a situation in which a conflict of interest would arise or manifest itself".

Up to that point, the ministry had avoided the worst of the criticism from the European Commission concerning the mismanagement of European Union funding. But just two months later, the ministry’s central finance and contracts unit, responsible for choosing projects eligible for money under the Phare pre-accession aid programme, had its accreditation revoked over its weak administrative capacity and the strong suspicions of fraud and conflict of interest in awarding the funds. To date, the unit has not regained EC accreditation.

One of Oresharski’s most unwavering opponents, his former deputy Georgi Kadiev, has accused Oresharski of repeatedly ending investigations into evasions worth millions of leva, because they were "small fry". "I’ll never forget his answer: sure, such things happen, but I will not let the macroeconomic stability be shaken up," Kadiev told broadcaster bTV.

With the economy no longer booming, that image of defender of macroeconomic stability is no longer that glowing and only the proximity of Parliament elections now looks the main reason Oresharski will likely see out his term.