Update 1-Regus 4-mth sales rise but earnings under pressure

*Regus 4 mth revenue 387 mln stg vs 334.5 mln a year ago

*Says market conditions remain tough

*Shares down 4.2 pct

(Adds details, shares, analyst comment)

LONDON, May 19 (Reuters) - Office rental company Regus Plc (RGU.L) reported a 16 percent increase in revenues for the first four months of the year as it opened new suites of offices but said pressure on occupancy and prices had impacted net income.

The company, which rents out ready-to-use offices for as little as half a day, said on Tuesday that revenue rose to 387 million pounds ($593.9 million) compared to 334.5 million pounds in the same period last year. The group opened 16 new business centres in the period, including its 18th in Manhattan.

Regus' net cash balance increased to 227.6 million pounds at the end of April as a one-off receipt of 18.5 million pounds helped offset the impact of a strengthening British pound.

Shares in the company, which operates over 1,000 business centres in about 450 cities around the world and ranks itself as the world's largest provider of workplace solutions, were down 4.2 percent at 80.5 pence by 0736 GMT.

Alex Magni, head of research at Noble, said 2009 promised to be a tough year with profits likely to suffer as unemployment rises and that Tuesday's statement indicated the rate of deterioration could be slightly sharper than he had anticipated.

"Given that the company is highly operationally geared, ongoing price declines will impact its profitability significantly," he wrote in a research note, predicting he would cut his above consensus 2009 and 2010 earnings estimates by 15 to 20 percent.

Magni said shares in Regus, which have gained more than 50 percent since mid March, had rallied in recent months thanks to its relatively strong cash position but that at 80 pence they did "not look particularly cheap", trading at 8.7 times expected cash adjusted 2009 earnings.