Beginning Sunday, some employers will be required to provide paid sick leave to employees. The requirement is one of a handful of new laws impacting businesses that go in to effect on Jan. 1.

The paid sick days bill was one of the most contested measures of the 2011 legislative session and passed the legislature only narrowly. When Gov. Dannel P. Malloy signed it into law Connecticut became the first state in the country to mandate paid time off for illness.

Under the new law, certain employers must provide workers with one hour of sick time for every 40 hours that employee works.

The law applies to companies with more than 50 employees but exempts the manufacturing industry and YMCA workers. It also does not apply to any company that already offers vacation or other time off to its employees.

The requirement was criticized by business groups like the Connecticut Business and Industry Association who said the measure sent the wrong message to employers in the state. Proponents saw the law as a matter of good public policy and health.

The legislature also made changes to health insurance requirements for businesses which expands coverage of certain medical tests and treatments. Those changes also go into effect on Sunday.

Joseph F. Brennan, senior vice president for public policy at CBIA, said that some of the new laws going into effect will make business more difficult for Connecticut employers. However, he said others that were passed during the special legislative session on jobs will help the state’s businesses.

During the jobs session, lawmakers passed a bill that made the annual $250 business entity tax payable every other year. Another new law combined and expanded three tax credit programs that businesses can use to create new jobs and hire qualified workers.

The Manufacturing Reinvestment Account program was established this year to allow 50 companies to invest up to $50,000 in their businesses. That number was expanded to $100,000 and 100 companies during the jobs session.

“Although there were both positive and negative measures passed in 2011, we’re hopeful that the bipartisan approach to our economy and jobs that we saw in the special jobs session will continue in 2012,” Brennan said in a press release.