TOKYO, Dec 29 (Reuters) - Japan’s Nikkei share average climbed to a three-decade high on Tuesday as investor risk appetite improved on hopes that the long-awaited U.S. pandemic relief package would be expanded. The benchmark Nikkei share average rose 1.63% to 27,292.37 by the midday break, having earlier hit its highest level since August 1990. The index was also on course for its biggest daily gain in five weeks. The broader Topix gained 1.05% to 1,806.84, hitting a level unseen since October 2018. Overnight, major Wall Street indexes notched record highs as optimism for an economic recovery increased following U.S. President Donald Trump’s signing of a $2.3 trillion pandemic aid bill. The U.S. House of Representatives voted on Monday to meet Trump’s demand for stimulus payments of $2,000 to qualified Americans, sending the measure on to the Senate for a vote. All but four of the 33 sector sub-indexes on the Tokyo exchange traded higher, with highly cyclical airlines and land transport among the top gainers on the main bourse The stocks that gained the most among the top 30 core Topix names were SoftBank Group Corp and Central Japan Railway, up 3.35 % and 2.83%, respectively. Among the top percentage gainers in the Nikkei index, Sumitomo Dainippon Pharma Co Ltd jumped 16.24%, followed by Mitsubishi Heavy Industries Ltd and IHI Corp, up nearly 6% each. Elsewhere, furniture retailer Nitori Holdings rose 1.44% after completing its tender offer for Shimachu Co . Shares of Shimachu inched up 0.18%. The Mothers Index of start-up firm shares rose 1.82%, hitting a one-week high. (Reporting by Eimi Yamamitsu; Editing by Subhranshu Sahu)