Google has been ordered to temporarily stop work on two datacentres in Finland after failing to do the necessary environmental impact assessments on its construction sites.

The planned datacentres in Muhos and Kajanni are part of a €13bn (£11bn) project across multiple sites in northern Finland by the technology company amid huge demand for space to house online infrastructure.

It comes after it emerged that Tuike Finland Oy, the company representing Google, had felled 330 hectares (815 acres) of forest in Muhos without completing an environmental impact assessment (EIA).

In Kajaani, the company has reportedly been logging across just under 200 hectares (494 acres) of land.

The Finnish Association for Nature Conservation said the sites had been reduced to “sand”, blaming the oversights on the “overheated” market for new datacentres.

On Tuesday, the Finnish Licensing and Supervision Authority (LVV) said it had issued a notice to the company to “immediately suspend” – by 23 October at the latest – “preparatory measures that significantly change the environment” of the two sites until the environmental impact assessment had been completed. Google has until next Wednesday to submit a written explanation.

The EIA is ongoing and expected to be completed later this year. But Google has gone ahead with “extensive preparatory measures”, including removing trees, stripping topsoil and constructing site roads, LVV said.

Tommi Muilu, the head of the environmental department at LVV, said: “In our opinion, the measures in question will change the environment and cause impacts, the identification and assessment of which are among the key objectives of the EIA procedure.”

If Google does not comply, LVV said it would consider enforcement proceedings and a fine.

In response, Google said in a statement “we understand the concerns” and that it had “fallen short of our own high standards”.

The company added: “We will study the LVV’s findings and follow their guidance. We acted in good faith under the Forestry Act, and ran nature surveys and put in place measures to protect high-value areas. As we continue our long-term work in the region, we are advancing our landscaping and biodiversity plans, which include tree planting across 130 hectares (321 acres) at Muhos.”

Tapani Veistola, the chief operating officer at the Finnish Association for Nature Conservation, said the malpractice across two sites appeared to be a “systemic problem”. The site at Muhos, he said, was “not a forest any more. It is a sand area.”

One of the reasons behind it, he said, was the enormous demand to build datacentres in Finland, which is leading companies to work as fast as possible and overwhelming small municipalities.

“The main reason behind everything is the overheated market situation that makes companies speed up processes so much. Also a lack of expertise in municipalities.”