The new facility in Staffordshire will replace a large temporary marquee that was put up several years ago, with the new building able to host a wider range of events.
National Memorial Arboretum head of marketing Sarah Oakden said: "We are determined to continue to broaden the event services that we can offer to visiting groups and businesses.
"The new building has been designed with the needs of event planners and conference organisers at the forefront of our minds, ensuring that we can meet all of their requirements."
At the moment the arboretum plays host to military, fraternity and business groups including hundreds of small and medium sized events for organisations around Britain.
It is also the stage for large set piece events working with The Royal British Legion on key dates throughout the year.
The new events space will allow conferences at the site, providing modern amenities and catering facilities capable of accommodating banquets of up to 300 people.
A new bar area will offer an informal space for drinks receptions, registrations, break-out sessions and evening functions.
As well as the stunning backdrop of the Arboretum, the space will offer the flexibility and facilities needed by event planners.
It will feature a large suite, which can be split into three, with six possible configurations and spectacular views across the arboretum site.
And a further four smaller meeting rooms will open up to provide a second, smaller suite.
The site can also accommodate theatre style events of up to 500 or small intimate meetings.
Glen Howells Architects have designed the building to make extensive use of glazing, with a light-coloured timber cladding and a steel frame.
The construction of the new events pavilion is set to begin, with completion due in autumn 2018.
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