A high-profile arbitration over millions of dollars worth of disputed paintings claimed by both the Beaverbrook Art Gallery and Lord Beaverbrook's descendants starts hearing closing arguments in Fredericton on Monday.

The arguments are expected to take up to two weeks, bringing a slow close to a set of hearings that have already lasted more than four weeks.

The two sides spent most of October presenting dramatically different stories about how the paintings came to be at the Fredericton gallery.

The gallery's lawyer pointed to magazine articles written when the gallery opened in 1959. The articles, some written by close associates of Lord Beaverbrook, referred to the 133 paintings as gifts.

But the Beaverbrook UK Foundation, controlled by the press baron's descendants, said those articles were meaningless. They pointed out that more than 40 years worth of the gallery's own documents acknowledged that the foundation owned the paintings.

Both sides tabled documents and called witnesses, and starting Monday they'll sum up all their evidence for arbitrator Peter Corey.

The dispute erupted in 2004, when the foundation asked for the return of two paintings, J. W. Turner's Fountain of Indolence and Lucian Freud's Hotel Bedroom. The foundation wanted to sell them for an estimated $30 million, and offered the gallery a $5 million grant in return.

The foundation was also willing to guarantee that the gallery could keep the rest of the paintings for at least 10 years. The galley rejected the deal, and the two sides eventually agreed to go to arbitration.

A separate dispute with the Beaverbrook Canadian Foundation over 78 other paintings will be heard in court next year at the earliest.