Labour leader Sir Keir Starmer will vow to bring in a new Armed Forces tsar to represent the military and their families if Labour wins the election.
The independent commissioner would be tasked with holding the government to account on issues affecting service personnel, Sir Keir will say ahead of the 80th anniversary of D-Day.
The plans were first announced last year but Labour has now committed to introducing the legislation as part of the first King’s Speech – set to take place on July 17.
Other laws to giving a “legal guarantee” to fair treatment for veterans would also be brought forward if Labour enters government, Sir Keir is expected to say.
He will pitch the party as “once again a party of service” during a visit to southern England on Wednesday.
It comes in a bid to shift perceptions of Labour’s defence stance following the leadership of Jeremy Corbyn, who was a critic of both Nato and Trident.
Labour has said it would meet the spending target as soon as economic conditions allow but declined to give a specific time frame.
Sir Keir said: “The ultimate service is that of our armed forces personnel and veterans. Britain owes a huge debt of gratitude for all they have given our country.
“My changed Labour Party, once again a party of service, will repay that commitment with a new package of support for veterans, service personnel and their families.
“We will establish a new armed forces commissioner and enshrine a new armed forces covenant fully into law.”
Shadow defence secretary John Healey said the party has “deep respect” for serving personnel and its new laws would begin to “right the wrongs for everyday forces life”.
“Labour’s new laws will improve everyday life for those who serve and the families who support them.
“They will begin to right the wrongs for everyday Forces life with a new independent champion, a legal guarantee of fair treatment and ensuring our veterans are properly respected,” he said.
“Labour will work with our armed forces communities to renew the nation’s contract with those who serve and the families who support them.
“Labour is totally committed to spending 2.5% of GDP on defence as soon as possible.”
Meanwhile, Rishi Sunak is seeking to draw a dividing line with his rival over the issue, having recently vowed to increase defence spending to 2.5% of GDP by 2030.
The Conservatives will be speaking about their offer to the Armed Forces community on Thursday as D-Day commemoration events kick off.
Johnny Mercer said: “Unlike this from Labour, we’ve worked hard to galvanise the main asks of wider veteran community and the veterans’ charities, and veterans should be excited about our plans to continue to drive progress towards being the best country in the world to be a veteran.”
By Emma Soteriou