* Rate decision 1145 GMT, news conference 1230 GMT
* Analysts expect rates to remain on hold at 1 percent
* Likely to confirm rates are appropriate, risks balanced
* ECB staff expected to upgrade economic forecasts
By Marc Jones
FRANKFURT, Sept 3 (Reuters) - The European Central Bank is expected to keep interest rates at 1.0 percent on Thursday, and President Jean-Claude Trichet is likely to preach caution on the growing hype of a full-blown euro zone economic recovery.
With the 16-country bloc enjoying a speedier-than-expected rebound from recession, all 80 economists polled by Reuters forecast ECB policymakers will leave rates at their current record low for a fourth month running.
The Governing Council will have new ECB staff economic forecasts to digest. Following surprisingly solid improvements in data, they are likely to show higher GDP than the last projections in June.
If the inflation outlook is also revised up, the forecasts will be the first across-the-board upgrades in three years.
Policymakers meet for their monthly policy meeting at 0700 GMT and announce their rate decision at 1145 GMT. Trichet is expected to warn at his news conference at 1230 GMT against getting carried away by the better data and stress that uncertainty remains.
"Things are improving and numbers have been coming in better, but policymakers have made it clear that there is still some time before they can sound an all-clear," said Dirk Schumacher, Senior European Economist at Goldman Sachs.
"They will certainly be no rate change and they will keep their stance that there is no change needed to policy rates or any other measures."
Data have surprised on the upside in recent weeks. Germany and France, the region's biggest economies, unexpectedly bounced out of recession, while manufacturing is picking up.
The euro zone economy shrank only 0.1 percent in the second quarter against the previous three months, following a 2.5 percent drop in January-March, and may return to growth in Q3.
TOO EARLY TO EXIT
The worry is that the momentum will be lost once central banks and governments around the world begin to take away the emergency support measures built up during the crisis -- a key topic at meetings later this week of the Group of 20 leading industrial and emerging nations.
German Bundesbank President Axel Weber said earlier this month: "It is too early to rein in the measures to support the economy."
European finance ministers appear to be in tune with the ECB. "Time has not yet come to withdraw from the fiscal stimulus," Jean-Claude Juncker, the chairman of the Eurogroup of euro zone finance ministers, said on Wednesday.
"We have to continue this effort in the course of this year and next year, then we have to agree on an exit strategy. We will discuss this."
Despite the intense interest from financial markets, Trichet is expected to give little away on the ECB's exit plans as yet.
Analysts expect him to repeat last month's view that the main refi rate is "appropriate", although any deviations in language will be jumped on.
"We expect the ECB to stay in wait-and-see mode in September; exit remains hypothetical," Deutsche Bank analysts wrote in a recent note. "The Council appears sceptical about the sustainability of the recovery. We expect the Council to let the recovery prove itself before calling the extraordinarily accommodative policy stance into question."
Economists polled by Reuters expect unchanged rates until the third quarter of next year and investors have eased back on their bets for early tightening.
Forward swap rates -- fixed rates which people are willing to pay to receive floating-rate payments over pre-agreed periods -- show that the average euro zone policy rate for the year starting in one year's time is expected to be 2.3 percent. This is up from expectations of a little more than 2 percent in July, but down from 2.7 percent in early August, according to Reuters data.
TENDER INTEREST
Another hot topic will be the ECB's second handout of 1-year cash, planned for the end of the month. Uncertainty remains about whether it will offer banks the money at 1 percent interest again -- as markets and analysts currently expect -- or bump up the price.
Trichet may reveal the rate during the news conference to give markets time to position themselves.
If the ECB did charge above 1 percent, markets would see this as a signal that Trichet and his colleagues expect rates to be higher in a year's time.
"The question is whether they add a spread or not," said Goldman's Schumacher. "Probably not in our view, but that is the main area of interest because it is likely to be where they start when they change their tone."
The ECB flooded markets with a record of 442 billion euros in one-year funds in late June. They are still digesting it and demand for the next operation remains tricky to predict.
"I've heard everything all the way from 80 billion up to 250 billion so it's going to be interesting to see what actually happens," said one London-based money market trader, who did not want to be named.
(Reporting by Marc Jones, additional reporting by Kirsten Donovan in London; editing by David Stamp)