* Budget revision seen in mid-June
* In Q1 budget deficit at 58 pct of annual plan
* Govt looking for more cost cuts, tax revenue
(Wraps Q1 gap, adds economist, details)
By Gabriela Baczynska
WARSAW, April 15 (Reuters) - Poland may raise its 2009 budget deficit target to as much as 21 billion zlotys ($6.5 billion) from 18.2 billion because of shrinking revenues that are already forcing deep spending cuts, a government source said.
"We will try not to raise the budget deficit much. Instead we'll make an effort to raise revenue and possibly reduce spending somewhere," the official, who asked not to be named, told Reuters on Wednesday.
"Preliminary estimates indicate that the deficit will rise to no higher than 21 billion zlotys. We'll make the revision in mid-June."
The finance ministry said on Wednesday the budget gap in the first quarter reached 10.6 billion zlotys, or 58 percent of the full year plan.
The centre-right government has pledged to keep a tight fiscal policy despite the global recession as it prepares Poland to join the pre-euro European Exchange Rate Mechanism (ERM2) in coming months and to adopt the common currency in 2012.
But economists now predict growth in the European Union's largest ex-communist economy will slow to 0.8 percent in 2009, below the government's "worst-case scenario" of 1.7 percent, and some say this makes upward revision of the deficit inevitable.
"Considering tha scale of the slowdown, such a deficit (21 billion zlotys) is unrealistic," said Grzegorz Maliszewski, chief economist at Millennium bank.
"After the revision the deficit will surpass 21 billion and will be close to 25 billion," he said.
On Tuesday, Poland, whose budget is in much better shapes than many other emerging market economies in the region, joined Mexico to seek a standby credit facility from the International Monetary Fund.
The one-year facility would give it funding in a possible cash-crunch, although Polish officials said they do not expect to need to use it. (Additional reporting by Kuba Jaworowski, writing by Chris Borowski)