The prince will give a keynote speech at Kensington Palace on Tuesday to mark International Mine Awareness Day.
More than 60 million people are estimated to still live with the threat of unexploded landmines.
He is expected to pay tribute to his mother ahead of the 20th anniversary of her death.
Princess Diana was known for her campaigning on the issue of landmine use and calling for them to be subject to an international ban.
In the months leading up to her death in 1997, she was pictured walking through a minefield in Angola, which was being cleared by the HALO Trust.
On her last overseas trip, she also went to Bosnia to meet victims who had been injured by landmines.
Prince Harry has made similar trips to Angola and Mozambique after becoming a patron of the trust's 25th anniversary appeal.
Now, he will speak out against the weapons at the Landmine Free World 2025 event, which will also commemorate the 20th anniversary of the Anti-Personnel Mine Ban Treaty.
Since the 128 countries signed the treaty to ban the use and production of anti-personnel mines, nearly 30 countries have been declared mine-free.
But there are still an estimated 60m people living with the daily fear of unexploded munitions.
Countries affected by landmines include those in Africa, Asia, Europe and the Middle East.
Somalia, Mozambique, Bosnia-Herzegovina, Kuwait, Cambodia, Iraq, Afghanistan, Angola and Iran have some of the highest numbers.
A Kensington Palace spokesman said: "Prince Harry is pleased to have this moment to recognise the significant contribution his mother made in this field, the progress which has been made by MAG (Mines Advisory Group), HALO, the UK government and other organisations, and the opportunity to continue raising awareness of making the world landmine-free by 2025."
Prince Harry is supporting a bid to rid the world of landmines by 2025, following in the footsteps of his mother Diana, Princess of Wales.