(Corrects typo in paragraph four.)
* Items from Roman hoard unearthed in 1970s
* Auction attempt in 1990 failed due to legal challenges
* Prime Minister calls treasure Hungary's "family silver"
By Marton Dunai and Gergely Szakacs
BUDAPEST, March 26 (Reuters) - Hungary unveiled on Wednesday Roman silverware it says was found in the country in the 1970s, smuggled abroad and recently bought back in a deal Prime Minister Viktor Orban said brought home a family treasure.
The seven decorated pitchers, platters and bowls were half the original 4th-5th century "Seuso treasure" and cost 15 million euros ($20.67 million) to buy, he said as they were put on display in the parliament building in Budapest.
Hungary says the objects were dug up near Lake Balaton in western Hungary during the communist period, smuggled to the West and not seen in public until a 1990 auction in New York that failed because of a dispute over where they were found.
Budapest has always claimed the treasure as its own.
Two people described only as "British siblings" contacted Hungary with a view to making a sale, Hungarian officials said.
"Hungary has reacquired and brought home seven pieces of the invaluable treasure," Orban said. "It has always belonged to Hungary. This is Hungary's family silver."
Orban is the favourite to win a general election on April 6 and recovering the Seuso silver, while primarily an issue of national heritage, could burnish his reputation as a defender of Hungarian national interests dear to many voters.
The treasure was named after a high-ranking Roman officer, Seuso, who probably buried his silver vessels before a military attack at the end of the 4th or beginning of the 5th century.
LONG HIDDEN TREASURE
The 14 pieces of the entire treasure were dug up in the 1970s by amateur archaeologist Jozsef Sumegh, who did not report it to Hungary's then-communist authorities.
"He presumably wanted to sell pieces of the treasure on the black art market but there is no proof of that because Sumegh is deceased," an official statement said, adding that he was found hanged in a cellar in western Hungary.
The treasure first surfaced at a 1990 Sotheby's auction in New York, where a consortium led by a British peer tried to sell it. But the sale was abandoned after Hungary, Lebanon and Yugoslavia all laid claim to the silverware, the statement said.
Lebanon withdrew its claim while those of Hungary and Croatia - acting as successor to former Yugoslavia - were turned down by a New York court.
The statement called the Seuso collection the most important silver treasure found so far at some 1,800 archaeological sites dating back to the late period of the ancient Roman Empire.
"The treasure arrived from London at the weekend," Laszlo Baan, the director of Hungary's Fine Arts Museum, told reporters. The British consortium that had tried to sell it in 1990 had not owned it for a while, he said without elaborating.
Baan said he had travelled to London to help identify the items at a tightly guarded compound. The price was good, he said, considering the 1990 asking price would be the equivalent of 100 million euros today.
Successive Hungarian governments since 1990 had never given up their efforts to get the Seuso treasures back, he said. Police kept the case open for a quarter century, uncovering clear evidence that the items belonged to Hungary.
"That is promising for the future, that sooner or later the whole treasure will return to Hungary, although the most central parts of it are here already," Baan said.
($1 = 0.7258 Euros) (Additional reporting by Krisztina Fenyo; Editing by Michael Roddy and Tom Heneghan)