Ontario's Court of Appeal has denied a group opposed to the city's public-private partnership to redevelop Lansdowne Park a chance to appeal an earlier defeat, effectively ending the last legal challenge to the redevelopment.

John Martin's Lansdowne Park Conservancy was the second group to launch a legal challenge of the city's partnership with Ottawa Sports and Entertainment Group.

The first group, Friends of Lansdowne, had earlier questioned the legality of the city's decision to enter into a sole-source agreement with OSEG but lost its legal challenge and again lost its appeal.

In March a lower court rejected Lansdowne Park Conservancy's legal challenge, saying it constituted an abuse of process and awarding the city $10,000 in legal costs.

The Court of Appeal, in dismissing the case on Tuesday, also awarded the city $1,000 in legal costs.

City solicitor Rick O'Connor, in a note to councillors, said while it is remotely possible that the Lansdowne Park Conservancy could appeal to the Supreme Court, he said given the previous decisions "it would be extremely difficult" to get the court to hear the case.

After losing its appeal, Friends of Lansdowne had said earlier this year they would not appeal to the Supreme Court.

In a note to his supporters, Martin called the ruling unfortunate and said the city still had an opportunity to change its plans and revisit its plans for Lansdowne Park.

"The deadline for park completion is June 2015 and there is more than sufficient time for the City of Ottawa to conduct a competitive bidding process and develop this public asset in a manner respectful of the heritage and public nature of the site," said Martin.

The $300-milion redevelopment of Lansdowne Park will include renovations to Frank Clair Stadium, the addition of a mix of condominium and retail space. OSEG has been awarded Canadian Football League and North American Soccer League franchises, both on the condition there is an appropriate stadium in place.