A majority of political parties in parliament's foreign affairs committee expressed support Friday for the government's proposal, and "the government will on the basis of [Friday's] meeting submit a bill to a parliamentary vote to strengthen the campaign against IS," a statement from the prime minister's office said.
The decision is seen as a response to a December request from the US that Denmark step up its efforts against Isis and a follow-through on Defence Minister Peter Christensen's pledge to US Secretary of Defence Ash Carter last month that Denmark would contribute to the international coalition against Isis wherever it is most needed.
Denmark joined the international coalition fighting Isis (alternately known as Islamic State or ISIL) in October 2014 and Danish F-16s flew 547 missions over northern Iraq, dropping over 500 bombs, before the jets were brought home for repairs in August.
Rasmussen said that with the new commitment, Denmark would “intensify” its fight against the terror group.
"We need to fight ISIL with focus and great force as it is unscrupulously terrorizing and killing innocent men, women and children," the PM said. "We must never five up the fight for peace and freedom."
The Defence Ministry said that with the new contribution, which in addition to the fighter jets and special forces troops will also include a C130 Super Hercules transport aircraft, Denmark would be among the nations with the largest military and civil presence in Iraq and Syria when measured per capita.
The foreign affairs committee's recommendations are expected to be put before parliament next month. The plan has the support of Venstre, the Danish People's Party, the Social Democrats, the Conservatives and the Social Liberals (Radikale), ensuring that it will pass.
The Danish contribution would be available from mid-2016 and the 400 soldiers would include pilots, support staff and 60 special operations forces.
It was not immediately known what the special forces would be assigned to do in Syria.
"It doesn't mean that the Danish soldiers will be in direct offensive combat. But they could be attacked, and therefore they will have a robust mandate," news agency Ritzau quoted Foreign Minister Kristian Jensen as saying after the foreign affairs committee's meeting.
Denmark currently has around 120 troops stationed at the Al-Asad air base near Baghdad, where they have been training Iraqi soldiers and Kurdish security forces.