World shares ground out a fresh record high on Tuesday, making it almost 50 for the year, although Europe tread cautiously as markets waited to see whether Spain's Catalonia region would push for independence later in the day.

Japan and South Korea returned from extended breaks to give Asia a lift, but the Catalan uncertainty meant it was a lower start for the euro zone's main bourses and for Spanish bond markets.

Catalonia independence

Catalonia's secessionist leader Carles Puigdemont is due to address the region's parliament in Barcelona. He could ask the assembly to vote on a unilateral declaration of independence from Madrid.

It is Spain's biggest political crisis since an attempted military coup in 1981. Madrid's IBEX stocks index drooped 0.5 per cent early on and it is now down almost 9 per cent since May, though a sharp rise in the euro has also taken a toll.

“We have not witnessed any relevant statement or signal by the separatists that would hint at a change of strategy ahead of today's discussion in the Catalonian parliament,” economists at Barclays wrote.

“Consequently, at this point, it seems likely that Catalan President Carles Puigdemont remains on track to announce a unilateral declaration of independence as early as today.”

German exports

The euro remained resilient. It hopped to a one-week high as data showed German exports had surged in August. Traders were also still upbeat on the currency after one of the European Central Bank's German policymakers called for an end to its stimulus.

There was also help from a weaker dollar which was down for a third straight day. The dollar index, which tracks the greenback against six major rivals, dropped 0.2 per cent to 93.533 and away from Friday's almost 3-month peak.

It gave the Turkish lira a breather having been sent sprawling to a nine-month low on Monday after the United States and Turkey scaled back visa services.

Mexico's peso hovered at its weakest in more than four months too, ahead of the latest round of talks over the North American Free Trade Agreement (NAFTA) on Wednesday.

Korea boost

In Asia, MSCI's broadest index of Asia-Pacific shares outside Japan climbed 0.6 per cent overnight, boosted by a 1.6 per cent jump in Korea as shares like Samsung caught up with some of recent world gains.

Japan's Nikkei reversed early losses to finish 0.6 per cent higher too, though China stocks staged a small retreat as investors cashed in on some of the gains that had taken them to a 21-month high in the previous session.

China growth target

China's Statistics Bureau on Tuesday said the country will have no problem meeting its economic growth target of around 6.5 per cent this year, and may even beat it. Such an outcome had been widely expected after a robust start to the year.

The offshore Chinese yuan rate surged to its strongest levels in more than two-weeks. The central bank had also set a firmer-than-expected official rate, suggesting authorities are keen to keep the currency in check ahead of next week's key national leadership meeting.

The stocks gains came in spite of tensions on the Korean peninsula. Russian Foreign Minister Sergei Lavrov told US Secretary of State Rex Tillerson in a phone call on Monday that an escalation was unacceptable.

That came after China had also called for restraint after US President Donald Trump warned over the weekend that “only one thing will work” in dealing with Pyongyang, hinting that military action was on his mind.

Crude oil, gold

In commodities, crude oil prices edged slightly higher, underpinned by OPEC comments signalling the possibility of continued action to restore market balance in the long-term.

But gains were seen as limited as oil production platforms in the Gulf of Mexico started returning to service after the latest US hurricane forced the shutdown of more than 90 per cent of crude output in the area.

Brent crude inched up 1 cent to $55.80 a barrel. US crude added 2 cents to $49.60.

Gold prices hit their highest in more than a week, though the gains were capped as expectations of another US interest rate hike this year limited appetite. Spot gold added 0.2 per cent to $1,286.52 an ounce.