The yen posted strong gains against major currencies as the main Nikkei index of Japanese stocks closed at a four-year high, while the dollar continued to slip as investors await durable goods orders data on Wednesday. Solid equities, strong economic data and the prospect of economic reforms being implemented after an expected victory for Junichiro Koizumi's LDP in the upcoming elections in Japan next month have all served to bolster the currency, analysts said. "With foreign investors flocking to Japan to capitalise on the tantalising prospects of the country's elusive recovery, the Nikkei and the yen look likely to derive a good deal of support looking forward," said Bank of New York analyst Neil Mellor. The latest opinion poll has shown support for Koizumi's party rising to 53 pct, suggesting not only that he will win the upcoming elections on Sept 11 but also increasing the chance of further economic reform in the coming months. Koizumi called snap elections recently after parliament failed to approve his key plan for reform of the Japanese post office. The yen rose to over six-week highs against the euro, while the dollar fell to a low of 109.46 yen. Elsewhere, the dollar also fell sharply against the euro, erasing some of the gains enjoyed on Friday on the back of expectations that US interest rates will continue rising. This week's US data is expected to be less positive, however, with durable goods figures on Wednesday set to show orders slipping back after two months of strong gains. US housing market reports tomorrow and Thursday meanwhile may also reveal some signs of cooling. "Data releases are unlikely to give much support to the dollar," said CALYON analyst Mitul Kotecha, adding that sentiment for the currency "remains weak" despite last week's gains. Also on the radar this week will be business sentiment surveys out of Germany -- the ZEW tomorrow, followed by the key Ifo survey on Thursday -- where investors will be looking to see whether the recent upturn in the euro zone economy