Australia has requested that three European companies submit their proposals for its future submarines project, SEA 1000, in a move to strengthen its fleet amidst increasing military expansion by China into South East Asia.

Defence minister Stephen Smith has said DCNS, Navantia and ThyssenKrupp subsidiary HDW, were invited to provide information on conventional submarine designs for the new project that is likely to run through the next 30 years.

The new vessels will not be nuclear propelled but are expected to be larger and more capable than the six existing locally-built Collins submarines, which are currently facing manufacturing and design problems.

Additionally, the country has also entered into a contract with Babcock to inform engineering development of the future submarines by studying the establishment of land-based propulsion systems test facility.

The project is a major national undertaking, outlined in the 2009 defence white paper, to acquire 12 new future submarines on the condition that they will be assembled in South Australia.

The white paper also revealed that more than $70bn will be spent over the next two decades to build submarines to bolster its military capabilities.

Australia has already budgeted an estimated A$65bn for the ongoing construction of new amphibious assault carriers, stealth fighter aircraft, tanks, helicopters and missile destroyers.

The country has also budgeted for the procurement of up to 100 Lockheed Martin F-35 fighters, which is double what Japan is seeking to purchase.

The Australian Government is expected to provide further details on the progress of the project in 2012.