Governments in many of the new democracies of Eastern Europe rang in the new year with one of the banes of their recent communist past: another round of price hikes.

In Poland, prices went up for gas, electricity and gasoline, while Hungarians will see rises this month in bakery products, sugar, flour, rice, cosmetics and household chemicals.In Czechoslovakia, a long-delayed price liberalization took effect with the introduction of new economic reform measures Jan. 1, which, although wide-ranging, fell far short of Poland's "Big Bang" of exactly one year ago.

In all these cases, however, the price hikes were the result of attempted adjustments to market prices and not - as in the past - an arbitrary attempt to put huge government deficits back into balance.

But the most important change in 1991 in Eastern Europe will be the transition into a hard-currency system of trade among countries of the former Soviet bloc.

After 40 years of an ineffective system of settling accounts that often boiled down to barter, trade transactions are now based on world prices.

But the adjustment will initially be a shock for the former members of Comecon. Turnover among them is expected to fall sharply initially due to the general economic crisis in post-communist countries and a decline in demand, particularly for capital goods.

In Poland, for example, the switchover to dollar settlements will mean a trade deficit of some $2 billion and a fall in turnover with East European partners of 30 percent.