Tue Nov 1, 2011 10:33am GMT By Fumbuka Ng'wanakilala DAR ES SALAAM (Reuters) - Tanzania's coffee prices rose at last week's auction, with a shortage of high-quality arabica beans in Colombia expected to boost prices in the east African country, the regulator Tanzania Coffee Board (TCB) said on Tuesday. Tanzania mainly produces arabica coffee and grows some robusta. Prices of its arabica normally track the New York market while those of robusta take their cue from London. State-run TCB said 16,995 60-kg bags were offered at the sale with 13,995 bags sold. A total of 23,379 of the 60-kg bags were up for sale in the previous auction, with 22,976 bags sold. "Overall average prices at the Moshi exchange were up by $0.58 per 50 kg for mild arabica compared to the last auction ...Average prices were above the terminal market by $34.34 per 50 kg," TCB said in its weekly report. East African coffee is normally packed in 60-kg bags, but the prices are quoted for quantities of 50 kg. TCB said coffee prices in New York markets were last week up by $4.20 per 50 kg, while London prices were down by $2.75 per 50 kg. "Arabica prices in Tanzania will remain on the high side because the supply of coffee from Colombia to the world market is still lower than expected," Primus Kimaryo, director of quality and promotion at the state coffee board, told Reuters. "Although our crop output will be less than last season because of drought, prospects are good ... We have received reports that coffee flowering has been good in the areas that have received substantial rainfall." Traders said they expected a steady supply of coffee to the weekly auctions from growers looking to take advantage of the good prices. "The supply of coffee has been good and farmers are very happy with the high prices they are getting for their crops," said a trader at a coffee exporting company in Tanzania. "We expect more than 30,000 tonnes of arabica coffee output in Tanzania this season and all these coffee will be sold at fair prices." Benchmark grade AA sold at $260.00-$326.00 per bag, from $276.00-$317.00 per bag previously. The average price was $297.91 per bag, from $300.15 previously. Grade A fetched $274.00-$316.00 per bag, from $277.00-$310.00 per bag previously and got an average price of $297.01, up from $295.10 previously. The newly introduced grade AB fetched $260.00-307.00 per bag, compared with $276.00-302.80 per bag at the previous sale, and got an average price of $293.95, up from $292.25 previously. TCB forecasts the 2011/12 (June/April) crop will fall to 45,000 tonnes in the continent's fourth-largest coffee grower -- after Ethiopia, Uganda and Ivory Coast -- from 56,247 tonnes in the previous season. The auction was held on Thursday and TCB issued the results on Monday. The next auction will be held on November 3.