By Katie Reid

ZURICH (Reuters) - Novartis AG <NOVN.VX> is likely to be the latest drugmaker to show it too has been hit by a collapse in sales of pandemic flu medicines when it posts its first-quarter results on Tuesday.

But the group, which has just closed its buy of eyecare group Alcon, is still expected to show robust demand for its other drugs and investors will be keen to see how its recently launched multiple sclerosis drug Gilenya, is fairing.

"We expect Novartis to continue to show that all divisions are performing well, despite the tough comparison with first quarter 2010 owing to the absence of $1.1 billion of swine flu vaccine sales this year," analysts at RBS said.

Despite the fall in swine flu sales, Novartis is expected to post a 13.8 percent jump in first-quarter sales to $13.8 billion, according to the average estimate in a Reuters poll.

Core earnings per share is seen slipping 3.4 percent to $1.40 as the strong Swiss franc weighs on its bottom line.

Cross-town rival Roche <ROGN.VX> posted a 47 percent slump in quarterly sales of Tamiflu, a pill used to treat flu, although this was still better than analysts had expected.

Like rivals, Novartis is also having to cope with healthcare reform in the United States and a push from cash-strapped governments in Europe to slash the prices of drugs.

Investors will eye full results due this week from other large drugmakers, including Johnson & Johnson <JNJ.N> and Abbott <ABT.N>, for more insight into the health of the industry.

The group, which is seen sticking to its 2011 goals, could also provide further guidance on synergies from Alcon.

(Editing by Jon Loades-Carter)