This week Greece’s culture minister, Michalis Liapis, pruned the powers of the country’s new archaeology chief, Theodoros Dravillas, after the dismissal and suicide attempt of the politician who preceded him in that post.

Christos Zachopoulos, the former secretary general of the Greek Culture Ministry and chairman of the Central Archaeological Council, jumped off the balcony of his fourth-floor home here last month after allegations that he was being blackmailed by his former office assistant, with whom he had had an affair. Mr. Zachopoulos, 54, survived the fall. But what began as a sex scandal has evolved into a political one that is being closely watched across the country. Mr. Zachopoulos was appointed to his post in 2004 by Prime Minister Kostas Karamanlis, a friend.

Mr. Zachopoulos’s former assistant has been detained while awaiting trial on charges of attempted blackmail, and Athens investigators have opened an inquiry into the former archaeology chief’s handling of ministry finances.

An Athens prosecutor is also examining at least 10 of an estimated 200 cases in which Mr. Zachopoulos, in his capacity as the head of the Central Archaeological Council, decreed that places could be removed from the list of protected archaeological sites.

The controversy seems to have eroded the moral authority of the Greek Culture Ministry, which has waged a high-profile campaign to reclaim ancient artifacts that it says were clandestinely looted from its soil and sold to museums abroad. Among the artifacts ceded recently are a priceless ancient gold wreath and a marble statue from the J. Paul Getty Museum in Los Angeles.

Among other decisions, investigators are examining a $90,000 grant sanctioned by Mr. Zachopoulos last month for a reforestation project at a group of archaeological sites in Salonika in northern Greece.

The Athens daily Eleftherotypia reported that the decision countered recommendations by a team of culture ministry experts who said the project could damage Byzantine monuments.

The scandal has set off a series of changes. For example, Mr. Liapis, the culture minister, said this week that Mr. Zachopoulos’s successor as the head of the archaeological council would not be allowed to vote twice to break a tie or to push through any other decision.

“We have to change some things so that there is greater transparency, so that public trust can be restored to this very important institution,” Mr. Liapis said at a news conference on Tuesday. “I’ve given orders to the new secretary general to strive for the biggest possible majority decisions in cases that come before the council.”

In July Mr. Zachopoulos used his second vote to allow two Art Deco buildings here — one of which was designed by a friend of Picasso’s and is viewed as an architectural landmark in Athens — to be removed from the protected list because it blocked the view from the restaurant of the new $178 million New Acropolis Museum. The issue had split the council 12-12.

But Mr. Liapis said the July vote was only “one of two cases in which Mr. Zachopoulos used his right to a second vote,” and that neither decision involved financial interests. Even so, opposition lawmakers now want to review several contracts approved by Mr. Zachopoulos.

Opposition lawmakers have also called upon Prime Minister Karamanlis to appear before a parliamentary committee. Their request has been dismissed by the government.