A New Zealand couple's wedding plans are in tatters - they are grounded in London because of volcanic ash and their guests are without the bride and groom in Tauranga.

Nicola Bernau and Karl Marett were to marry on Friday in front of family and friends.

But a devastated Miss Bernau last night told her father Tim Bernau - who was to walk her down the aisle - she was going to have to cancel.

"She wanted to pull the plug half an hour ago and I said no leave it, for whatever reason, leave it until ... I didn't mind being phoned at 2 or 3 o'clock in the morning," he told the Herald.

"But the answer's going to be the same, I'm sure it is."

Mr Bernau said his daughter, 33, was "naturally pretty upset".

"Of course, we are not going to pull the plug here without her consent. We have got problems with guests, we have got problems with accommodation, and people flying out from the UK, flying out from Australia for the wedding. So everyone is affected. But it's her day.

The couple, who met in the UK, were to fly from Heathrow to Auckland last Saturday but were thwarted by the ash from Iceland that has cancelled thousands of flights.

The church and reception venue could be rescheduled, but the question was whether people who travelled from far afield could make it at a later date, Mr Bernau said.

Meanwhile, applause, cheers and whoops of joy rang out from New York to Asia to Paris late last night (NZT) as airplanes gradually returned to the skies.

But only limited flights were allowed to resume, and British officials said London airports - a major hub for thousands of daily flights worldwide - were unlikely to reopen until tonight, at the earliest.

Air traffic controllers warned a new ash cloud was headed for major air routes, prompting British Airways to cancel its short-haul flights, and several countries closed airports again or curtailed use of airspace.

The Eurocontrol air traffic agency in Brussels said it expected some 55 to 60 per cent of flights over Europe to go ahead overnight, a marked improvement over the past few days.

By late last night, 10,000 of Europe's 27,500 daily flights were scheduled to go.

"The situation today is much improved," said Brian Flynn, deputy head of operations at the agency.

"The outlook is that bit by bit, normal flights will be resumed."

But an international pilots group warned that ash remains a danger, and meteorologists say Iceland's still-erupting Eyjafjallajokull volcano isn't ready to rest yet, promising more choked airspace and flight delays to come.

A Eurocontrol map showing the ash cloud listed only the airspace between Iceland and Britain and Ireland as a no-fly zone, with much of the Baltic Sea and surrounding area.

The ash cloud also spread westward from Iceland, toward Greenland and Canada's eastern coastline.

Even where UK flights resumed, at the Edinburgh and Glasgow airports in Scotland, the service was limited.

"It's really just Scottish domestic flights, maybe a couple of international ones, there's one going to Iceland - yes, it's ironic, isn't it?" said Glasgow airport information officer Steven Boyle.

About 5000 New Zealanders had been due to fly to Europe this week, but their plans are in limbo. Air New Zealand yesterday estimated the cost to its business of its flight disruptions at $500,000 a day.

Another Kiwi affected by the ash crisis is Diana Wright, who should be at her father's funeral in the UK tomorrow.

Instead, she is back at her home in Wellington after three days stranded in San Francisco because of the ash. "I was able to speak to dad on the telephone and tell him I loved him before he died, but I needed to see him to say goodbye."