Auction house Christie's indefinitely cancelled the sale in London of 85 works by Spanish artist Joan Miro owned by Portugal due to the legal "uncertainty" surrounding the works.
A Portuguese court approved the sale of the works, whose value is estimated at around $47 million, but the auction house cancelled the sale on Tuesday.
Christie's has a legal responsibility to ensure that customers will not have "any problems" registering ownership of works, a spokesman for the auction house said.
The Portuguese Attorney General's Office recommended the suspension Monday of the sale in response to a request from five socialist lawmakers.
The legislators presented evidence last Friday of alleged irregularities in the issuance of the permits to move the works out of the country.
The government became the owner of the Miro works when it nationalized Banco Portugues de Negocios, or BPN.
BPN purchased the 85 works in 2006 and had to be bailed out by the government two years later amid a financial scandal.
Christie's estimated in 2008 that the Miro works were worth $108 million, but the latest estimate is less than half that amount, causing an uproar in Portugal.
Some Portuguese art experts opposed to the sale contend that the Miro collection could still be worth more than $108 million.
The General Heritage Administration said in a report to Parliament on Wednesday that some procedures were not followed correctly in sending the Miro works out of Portugal.
The request to allow the works to leave the country was filed 20 days before the planned auction, while the law sets a 30-day minimum period, former General Heritage Administration director Isabel Cordeiro, whose term ended on Wednesday, said.
Parvalorem, the state-owned company listed as the official owner of the works, filed the required forms only after heritage officials advised it that it had to fulfill a series of requirements before the scheduled Feb. 4-5 auction at Christie's, Cordeiro said.
The General Heritage Administration learned of Parvalorem's plans to sell the works in the press, Cordeiro said.
The government's decision to sell the Miro collection has drawn wide public opposition, with more than 9,000 people signing an online petition against the sale.
Joan Miro (1893-1983) was a Spanish painter, sculptor and ceramicist known for his colorful surrealist works. EFE