* Portuguese parliamentary vote jitters knock euro
* Yen trapped by wariness over intervention
* Pound supported after inflation data, BoE minutes awaited
By Hideyuki Sano and Naomi Tajitsu
TOKYO/HONG KONG, March 23 (Reuters) - The euro slipped on Wednesday, retreating from a 4 1/2-month high against the dollar as worries about debt problems in Portugal and Ireland sapped appetite for the currency and its near-term outlook is seen hinging on whether Lisbon's make-or-break attempt to garner parliamentary support for its austerity measures will succeed.
Portugal's political crisis has quashed the latest rally in the euro, which climbed to $1.4249 earlier this week, but some analysts said any selling in the euro if the government fails was unlikely to extend far below $1.41, given expectations EU leaders are close to agreeing the details of a debt-rescue fund, while euro zone interest rates are widely seen rising next month.
Lisbon's parliament will vote on the government's latest austerity measures on Wednesday and Prime Minister Jose Socrates has threatened to resign if the opposition fails to approve the measures, setting the stage for a potential collapse of his minority government a day before a European summit where leaders are due to discuss steps to deal with debt problems. [ID:nLDE72L1IO]
"The Portugal situation has put a spanner in the (euro's rally) with the suggestion the government may fail today, and the implication would be the resulting uncertainty would push the country towards a bailout," said Robert Ryan, senior G10 currency strategist at BNP Paribas in Singapore.
"But would that come as a big surprise to the market? I don't think so ... We could see a dip below $1.41 but I don't think we will go to much further. The ECB has made it clear that regardless of the situation with the periphery, they will go ahead with a hike in April."
Also causing some uncertainty about the health of the euro
zone were rumours that Allied Irish Banks (AIB)
AIB said in a statement that it would pay the coupon due on Wednesday as scheduled.
The euro traded at $1.4160
On charts, the euro was poised for a pull-back to support at $1.4030/50 -- intraday peaks from earlier this month -- but only a drop below the $1.40 level would suggest a peak had been put in place and its solid uptrend was reversing.
The euro has rallied nearly 6 percent against the dollar so far this year, and is hovering on the threshold of its highest since January 2010. Given ongoing debt problems plaguing weaker euro zone countries, some analysts anticipate a retreat in the euro in the coming months, adding that current levels offered a good chance to lock in profits.
"Given how strongly the euro has performed in the last few weeks, uncertainty about Portugal could give people a reason to take profits, and possibly sell it, so we would expect some downward pressure from here," said Chris Gothard, head of FX for Brown Brothers Harriman in Hong Kong, adding that a slide to $1.4050 in the near term was possible.
The European Central Bank is widely expected to raise its benchmark rate by 25 basis points from a record low 1.0 percent next month. Some in the market believe the euro's yield advantage over the dollar will provide some cushion for the currency, while others caution that monetary tightening while weaker euro zone countries were suffering may spell trouble for the single currency.
Sterling
Investors were also anticipating the UK government's 2011 budget, to be announced on Wednesday, to see if it it will bolster faltering growth without compromising on a tough austerity programme to get public finances back in order.
YEN STALLED
The dollar
The G7 may have sold around 530 billion yen ($6.5 billion) last Friday as they intervened to weaken the currency, data from the Bank of Japan showed on Tuesday, far less than the approximately 2 trillion yen indicated by market talk. [ID:nL3E7EM1IH]
Market participants were wary of Japanese authorities returning to sell the yen aggressively, particularly below 80.50 yen, where they came in last Friday. At the same time, few in the market expected big gains in the dollar, adding that a rise back to around 83 yen, where the dollar traded before Japan's devastating earthquake, was unlikely.
"The G7 may have wanted to push the dollar/yen back to its levels before its tumble last week but they won't try to push it back to its levels before the earthquake. They'll leave it to the markets from here," said Ayako Sera, market strategist at Sumitomo Trust in Tokyo.
Many in the market anticipate more downside in the dollar in the coming days. Some traders say a slide under 80 yen is possible, although a sharp fall below 79 yen before the end of the month was unlikely due to wariness about possible intervention.
On the upside, heavy exporters' offers are already lined up above 82.00 yen, with more seen around 83.00 yen, and an options trader at a Japanese bank on Tokyo said he suspected the balance of dollar/yen flows would be tilted towards dollar selling during the last stretch of Japan's financial year, ending this month, as Japanese exporters are likely to sell.
The last week of March commonly sees a mix of dollar flows including exporter selling and buying by investors related to overseas investments in the new year. Still, market participants have been speculating that such buying demand may be limited this year given the recent drop in Japanese equities, which could sap domestic investors' risk appetite. (Additional reporting by Masayuki Kitano and Reuters FX analyst Rick Lloyd in Singapore; Editing by Ramya Venugopal and Richard Borsuk)