The white paper is expected to outline how reservists will work more closely with full-time regular members of the army.
A £42m budget will be provided for new kit and extra training for reserve forces.
It is also expected to reveal financial incentives for small firms employing reservists.
Concerns over the pressure that would be placed on employers to free up their staff for military duty have been highlighted by Wales This Week.
We are asking a heck of a lot from employers... the majority of Welsh companies are small to medium sized and they can't afford for people to go away for a long period. This will be part of the problem that will have to be solved if we want to make an effective Territorial Army in Wales.
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Feeling humid with heavy showers and thunderstorms moving north overnight into Sunday.
Four people, including three children, were taken to hospital to be checked for smoke inhalation.
Heavy rain and thunderstorms will affect many parts of Wales this weekend - particularly during Saturday evening.