PORTLAND — Cigarette sales are rising in Maine for the first time in more than 20 years, and New Hampshire’s higher cigarette taxes may be one reason why.

According to Maine Revenue Services, the number of cigarette tax stamps sold in Maine during the first six months of 2010 is up about 5 percent over a year ago.

Officials say there are a number of factors — a crackdown on illegal Internet sales, a rise in youth smoking rates and last year’s increase in New Hampshire’s cigarette tax to $1.78 a pack, only 22 cents a pack less than Maine. With New Hampshire no longer the land of cheap cigarettes, more Mainers may be buying their smokes at home rather than going across the border.

New Hampshire officials say cigarettes sales have fallen since the tax hike.