Schools across South Australia will start work on upgrades and expansions with more than $50 million of investment announced for infrastructure projects.

The funding will allow the Department for Education to progress urgent upgrades and replace assets that have reached the end of their serviceable life, at some of its highest priority sites.

In the metropolitan area, multi-million dollar improvements will be made at Fairview Park Primary School, Fulham Gardens Primary School and Taparra Primary School.

Located in Adelaide’s north-eastern suburbs, Fairview Park Primary will receive $10 million to replace outdated buildings with modern new facilities.

In regional South Australia, Fraser Park Primary School in Murray Bridge will also receive $10 million, with the funds to go towards demolishing old transportable buildings and replacing the preschool.

There will also be $5 million for Mt Barker High School to support upgrades to help with capacity and to build new physical education and food technology areas.

Oakbank School in the Adelaide Hills has also received $15.9 million, announced as part of the release of the State Government's 20-Year Infrastructure Plan for Education and Care, to rejuvenate and update the site’s facilities.

Fairview Park Primary School Principal Becky Jones said the announcement was "wonderful news" for the school community, which was "beyond excited".

"Fairview Park is blessed to have beautiful surroundings, and our school has worked hard to make the best of our ageing infrastructure, but there is only so much that can be done," Ms Jones said.

"This school is 50 years old next year, and having new buildings and teaching spaces for our students and staff will be the best possible birthday present."