Alicia Castro, the Argentine ambassador to London, has decided to turn down an invitation to Margaret Thatcher's funeral, which will have a strong Falklands War theme.
David Cameron's official spokesman said on Tuesday morning the decision to refuse was a "matter for the Argentine ambassador".
Argentine president Cristina Kirchner was not given an invite to Wednesday's ceremony amid a simmering row over the sovereignty of the islands.
The territorial dispute was reignited last year as the 30 year anniversary of the 1982 war, in which Thatcher ordered a Royal Navy task-force to the South Atlantic to recapture the islands, approached.
The former prime minister's funeral will have a heavy Falklands war theme, with two brothers who survived the Argentine attack on the Sir Galahad, in which 48 men died, having been selected as pall bearers.
In total 700 members of the Army, Royal Navy and Royal Air Force will take part in the funeral.
Argentine Foreign Minister Hector Timerman has dismissed the apparent snub of him and his president as "another provocation".
"It does not matter to me to be invited to a place where I don't want to go," he told a local Argentinean radio station.
There will be a private service for Thatcher at the Chapel in the House of Commons on Tuesday afternoon, attended by her family and senior figures from both Houses of Parliament.
The rest of the seats in the historic chapel have been offered to members and staff of both Houses who knew or worked closely with the former premier or served her in a personal capacity.
After the service, the chapel will remain open for members of both Houses to pay their respects and the Speaker's Chaplain, the Rev Rose Hudson-Wilkin, will maintain a vigil through the night.
Her coffin will leave the Palace of Westminster by hearse tomorrow before being transferred to a gun carriage for the final leg of its journey to St Paul's.
