(Adds Estonian operator in paragraphs 1, 5, 8) OSLO, Oct 9...

(Adds Estonian operator in paragraphs 1, 5, 8)

OSLO, Oct 9 (Reuters) - Preparations were underway to inspect a subsea gas pipeline connecting Finland and Estonia in the coming days after a sudden drop in pressure was detected, Finnish gas system operator Gasgrid and its Estonian partner Elering said on Monday.

The Balticconnector link was shut early on Sunday on concerns that gas was leaking from a hole in the 77-kilometre (48 mile) pipeline.

Gasgrid said it could take months or more to repair if a leak is confirmed.

The operators will survey the seabed structure to identify the exact location and cause of the outage but a conclusion could still be days away, they said.

Meanwhile, no potential causes for the outage could be ruled out for the time being, including sabotage, an Elering spokesperson said.

The pipeline between Inkoo in Finland and Paldiski in Estonia crosses the Gulf of Finland, an arm of the Baltic Sea that stretches eastwards into Russian waters and ends at the port of St Petersburg.

In 2022, the larger Nord Stream gas pipelines which cross the Baltic Sea between Russia and Germany were damaged by explosions that authorities have said were deliberate acts of sabotage.

Elering said shortages of gas were not foreseen in the Baltic region even if the pipeline were to remain inoperable throughout the winter, as supplies were still available from storage in Latvia and from Lithuania's LNG import terminal.

The pipeline opened in December 2019 to help integrate gas markets in the region, giving Finland and the Baltic nations of Estonia, Latvia and Lithuania more flexibility of supply.

Finland last year leased a floating storage and regasification unit (FSRU) to receive liquefied natural gas (LNG), replacing supplies from Russia which were cut in the wake of Moscow's invasion of Ukraine.

Situated at Inkoo, the Exemplar FSRU vessel has supplied gas to Estonia via the Balticconnector.