SECRET Defence documents have revealed an extraordinary litany of reasons why it fears letting women fight in frontline combat roles - including increased sexual harassment, litigation, deaths and battlefield pregnancies.

The concerns include "almost certain" personal privacy problems while working with men, males trying to protect females in war zones and women being considered not "credible" in combat.

Revealed: List of reasons defence fears women warriors

Serving female Defence personnel will be able to apply for new frontline combat roles within three months.

But females outside the Army, Navy and Air Force will have to wait another three years before they can sign up.

The Australian Defence Force implementation plan to open the remaining 7 per cent of combat roles to women also reveals some equipment and facilities will have to be tweaked for new female recruits.

Under the plan - recently signed off by Defence chiefs and obtained by The Sunday Telegraph - in-service transfers can be applied for in January next year but actual deployment will rely on vacancies and availability.

But a risk matrix log of 71 issues, their likelihood, consequences and mitigation measures warns of possible injuries, non-acceptance from personnel and "almost certain" damage to the reputations of the ADF and government if the policy was bungled.

Defence "in-confidence" documents also list pregnancies on deployments from "inappropriate relationships" and women being killed in combat, captured by the enemy or men protecting females on the battlefield as sensitive issues requiring its management."The community is divided on the issue with strong views opposing the move at one extreme and firm support with caveats at the opposite extreme," the brief concluded.

In the September 2012 risk log obtained by The Sunday Telegraph, Defence believed there could be a "high" risk that government may apply pressure to bump up female numbers in new army combat roles, amid other risks that no women would apply or high percentages would fail physical standards tests.

But the department said it would reinforce to ministers the threat to capability and deploy senior service chiefs to intervene and influence government if it occurs.

Defence Personnel Minister Warren Snowdon yesterday ruled out any interference.

The revelations are the first time the full gamut of Defence's worries have been revealed since the controversial new gender-neutral frontline strategy was revealed last year. It will open the remaining 7 per cent of positions to females, including infantry, artillery and armoured corps roles, air force defence guards and navy clearance divers.