World shares firmed slightly after a four-day retreat on Monday with investors still cautious about global economic recovery and shrugging off the rather neutral conclusion to a weekend G20 leaders' summit.

The Group of 20 leaders meeting in Toronto agreed on Sunday to take different paths for cutting budget deficits and making their banking systems safer.

Most countries had contrasting priorities, reflecting the uneven economic recovery across the globe.

Worries have risen in recent weeks that the recovery is slowing, underlined on Friday by U.S. growth data that was less robust than expected.

This has led to fears that countries such as Germany and Britain are trying to cut their deficits too soon.

There are some legitimate doubts. Government finances in most of the mature economies are really in trouble, so we have to do something about that. But it will probably pressure growth, said Luc Van Hecka, chief economist at KBC Securities.

MSCI's all-country world stock index was up 0.2 percent with its more risk-sensitive emerging market counterpart gaining 0.5 percent.

The main index had four days of losses last week following a 10-session rally. It is down 7 percent for the year-to-date, reflecting the first half's volatility over economic recovery and the euro zone's sovereign debt crisis.

European shares struggled to keep up early gains. The FTSEurofirst 300 was up 0.2 percent.

Earlier, Japan's Nikkei slipped half a percent, with prospects of a stronger yen weakening sentiment.

DOLLAR CALM

The dollar edged up after faltering in Asia on concerns about the U.S. economic recovery and the euro remained under pressure by euro zone debt concerns.

The market showed little reaction to the Group of 20 summit.

It's mostly a compromise and nothing hugely material, said Lee Hardman, currency economist at Bank of Tokyo-Mitsubishi UFJ.

The focus this week is on the recovery weakening, which is taking some upward momentum out of the dollar, most evident against the yen, as the euro remains hampered by its own issues.

The dollar was up 0.2 percent against a basket of currencies while the euro fell 0.1 percent to $1.2355.

Euro zone government debt yields were slightly higher.

(Additional reporting by Atul Prakash and Tamawa Desai; Editing by Toby Chopra)