The ruins of a sacred temple have been uncovered that predates the Incas, say archaeologists.

Some of the structures hidden in a forest of eucalyptus trees predate the Inca empire but were then significantly developed and expanded, with a roadway and irrigation, says a team from Peru's National Institute of Culture.

Archaeologists were lucky to find the ruins at all, as part of the structure was destroyed by dynamite blasts in the early 20th century, when the site was used as a stone quarry.

The ruins lie in the Archaeological Park of Sacsayhuamán, north of Cusco city, a 3,000 hectare site that is home to many Inca monuments, notably Sacsayhuamán ("satisfied hawk" in Quechua, the Inca language), Qenqo, a shrine on a hilltop where maize beer was stored for rituals, Puca Pucará, the "red fortress", and Tambomachay, home of a water cult.

The newly-found ruins are located in Cochapata, 170 metres from the archaeological complex of Qenqo and 1,500 metres from the huge stone block walls of Sacsayhuamán Fortress.

The 250 square-metre temple has 11 rooms of different sizes, some of them are the shape of a half Chacana (an Incan religious symbol), a three-stepped cross representing the southern cross and symbolising the three tiers of Inca life, explained Oscar Rodríguez, archeologist.

The rooms were thought to hold mummies and idols. "This was an adoration centre," says Rodriguez, a researcher at the Sacsayhuaman park that, like the ancient Incan citadel of Machu Picchu, is a popular tourist destination.

The roadway, buried for hundreds of years under a metre of soil, is believed to have formed part of a network connecting Sacsayhuaman's buildings.Archaeologists are also busy unearthing a hydraulic system, which may have been used to supply water.

The team is still waiting for carbon dating tests, but ceramics and construction style provide important clues. Remnants of Ayarmaca ceramics are scattered throughout the site. The Ayarmaca occupied the region from 900 to 1200.

They will spend the next five years investigating evidence of other buildings near the temple, which was made of stones and adobe. "It's from both the Inca and pre-Inca cultures, it has a sequence," Washington Camacho, director of the Sacsayhuamán Archaeological Park "The Incas entered and changed the form of the temple, as it initially had a more rustic architecture."

He adds: "The temple is one of the most important in the Sacsayhuamán site." The Spanish conquered the Incas in 1532.