PARIS, July 21 (Reuters) - Canadian investment fund La

Caisse will join up with Britain's Amber Infrastructure to

become the largest private investors in Britain's Sizewell C

nuclear project, French newspaper Les Echos reported on Monday.

The business newspaper said that final decisions on the

investment would be made on Tuesday if all went well, citing

unnamed sources.

The pair of private investors would provide 25-30% of the

capital for the project, the cost of which has ballooned since

initial announcements, Les Echos reported.

Britain's government has committed 17.8 billion pounds to

the project but has continued to search for investors.

Reuters previously reported that U.S.-listed investment fund

Brookfield would take a stake of more than 20% in the project in

exchange for funds to finance the plant's development and that

British utility Centrica could also play a role.

French nuclear energy utility EDF is set to invest around

1.1 billion pounds ($1.48 billion), taking a 12.5% stake in the

project.

Amber Infrastructure and Brookfield did not immediately

respond to requests for comment. La Caisse, EDF and the UK

government declined to comment.

Britain is vying to build new nuclear plants to increase

energy security and to reach climate targets. Southeast

England's Sizewell C plant is expected to produce electricity to

power 6 million homes when operational.

($1 = 0.7419 pounds)