TALLINN, July 12 (Reuters) - A Chinese-funded Finnishcompany working on a Tallinn-Helsinki undersea tunnel projectsaid on Friday it will work with three Chinese companies on thefinal design and building of the 100 kilometre (60-mile) tunnel,which forms part of Beijing's Belt and Road initiative.

FinEst Bay Area Development said it signed a memorandum ofunderstanding with China Railway International Group, ChinaRailway Engineering Company, China Communications ConstructionCompany, and financier Touchstone Capital Partners.

"The partner companies are the largest in the world in theirown fields of expertise," said Peter Vesterbacka, co-founder ofFinest Bay Development company.

The new partners were needed as Finland and Estonia hadlimited resources in tunnel boring and highspeed traintechnologies, he said.

In March the project got a provisional 15 billion euros ($16.9 billion) from China's Touchstone Capital Partners.Roughly 12.5 billion euros will go into construction.

Beijing's Belt and Road initiative seeks to link China bysea and land with southeast and central Asia, the Middle East,Europe and Africa, through a network along the lines of the oldSilk Road as well as through an Arctic route.

Finland and Estonia have for years considered linking theircapitals, which are divided by the Gulf of Finland. The tunnelwould cut the travel time to 20 minutes from the two-hour ferryride, conducted by thousands of people daily.

A 2017-published feasibility study commissioned by the twogovernments said the planned tunnel could open in 2040 but thebuilders said it could be built by the end of 2024, with someparts opening already before.

The project is yet to secure backing from the twogovernments.

($1 = 0.8887 euros)

(Reporting by Tarmo VirkiEditing by Alexandra Hudson) ((tarmo.virki@thomsonreuters.com; +372 564 4562;))