Portugal's government finalised plans to privatise Lisbon's public transport network Wednesday by signing a concession accord with Spanish group Avanza, the Portuguese finance ministry announced.

The leading private operator of public transport systems in Spain, Avanza won a bid for the contract in June over French rivals RATP and Transdev, Britain's National Express and Barraqueiro of Portugal.

The concession grants Avanza management of the Lisbon subway and municipal bus service Carris -- whose fleet will be renewed as part of the deal -- saving the Portuguese state around 215 million euros ($241 million) in annual operating costs, according to the ministry.

The accord was one of the last major privatisations undertaken by Portugal's ruling centre-right government in a mix of reforms accepted by Lisbon for its 2011 international bailout from the country's deepening debt crisis.

That last push came less than two weeks before Portugal's legislative elections, and followed a legal challenge by Lisbon's former socialist mayor Antonio Costa to derail the privatisation plan of Prime Minister Pedro Passos Coelho -- who is facing a tight race to return to power.

As part of that government campaign, operation of Porto's subway system was granted to private French group Transdev last September, while a Spanish affiliate of National Express won the concession for the city's bus system.

Owned by Mexican investors, Avanza operates public transport systems in 28 Spanish cities -- including Madrid and Saragossa -- and two municipalities in the north of Portugal.