"We don't want to be mediators but Mr Solana hopes to find a way of reinvigorating the process and solidifying the national consensus at this time of trouble," said Mr Solana's spokeswoman, Cristina Gallach.
Lord Robertson is accompanied by the ambassadors of all 19 Nato members.
The meeting follows Monday's all-party talks aimed at addressing Albanian grievances.
Ilir Meta said the situation was totally different to that in Kosovo two years ago, adding that his government would give no support to the rebels.
Police checkpoints have been set up on main roads between Albania's coast and its border with Macedonia.
A 48-hour lull in fighting with rebels in Macedonia was ended by new gunfire in the village of Selce, above the flashpoint town of Tetovo.
BBC correspondent Nick Thorpe says the recent fighting has hardened the positions of both Macedonian Slavs and Albanians.
Macedonian President Boris Trajkovski, who chaired Monday's talks, said more discussions would follow on proposals which he had put forward.
He has the delicate task of satisfying the Albanians' demands for more rights without provoking a backlash from the Slav majority. There is pressure from the outside world to turn the country back from war.
Boycott
The EU's foreign affairs commissioner, Chris Patten, and security chief, Javier Solana, travelled to Skopje on Monday for more talks with the president.
"We don't want to be mediators but Mr Solana hopes to find a
way of reinvigorating the process and solidifying the national
consensus at this time of trouble," said Mr Solana's spokeswoman,
Cristina Gallach.
Monday's talks were attended by the largest ethnic Albanian party, the Democratic Party of Albanians, which is in the governing coalition.
But they were boycotted by the main ethnic Albanian opposition party, the Party for Democratic Prosperity.
Demands
The leader of the DPA, Arben Xhaferi, has threatened to pull out of the government unless its demands are met within a month.
He has also warned that the rebels will return if progress is not made.
On Monday morning, the army had reported a completely quiet night, and the authorities said the revolt was at an end. The border with Kosovo is due to reopen on Tuesday.
However, their claim a week ago to have successfully driven rebels from the hills around Tetovo proved premature.
It is not clear whether the rebels are dead, have fled into Kosovo, or have blended back into the civilian population.
But correspondents say the brief rebellion has changed the political situation in Macedonia. The government now accepts that the grievances of the Albanian minority have to be addressed, and the hand of Albanian politicians strengthened.