"I have discussed today the amendments to the constitution ... in relation to troop deployment," Robertson said at a press conference in Budapest with Hungarian Prime Minister Peter Medgyessy.

"I have a message for all of those involved in politics in Hungary, and that is to get this sorted out as quickly as possible."

Under the Hungarian constitution, a decision to send troops abroad needs to be approved by a two-thirds majority in parliament.

Medgyessy's government, which only has a narrow majority, in June got approval from the legislature to send 300 troops to Iraq but only after a month of debate in which the opposition twice voted it down.

"We expect the countries of the alliance to be able to accept all responsibilities and that includes the willingness to deploy forces," Robertson said.

"It's not a matter of politics.., it's a matter of simple practicality."

Medgyessy said he would seek opposition support for a change in the constitution and hoped parliament could pass an amendment in the autumn.

"Taking on international responsibility can only be done if the government has the means to react quickly and effectively. We need a constitutional amendment for this," he said.

"I have great confidence that we can find common ground with the opposition. The nation's international reputation is at stake."

Hungary joined the North Atlantic Treaty Organisation in 1999.

Robertson is on a farewell tour of NATO states before he steps down as secretary general of the alliance in December.

WAR.WIRE