The logo of Miller Industries is seen on a component.

Miller Industries grew net sales by more than a third over the last year, but warned the winding down of government contracts may slow growth.

The Chattanooga-based tow truck manufacturer announced Wednesday that net sales for 2011 reached $412.7 million, up 34.5 percent from the $306.9 million of sales in 2010.

Fourth-quarter sales hit $109.4 million, up more than 37 percent from the year before.

"We are seeing some gradual improvement in demand within our domestic markets and are hopeful that the environment will continue to improve," Jeffrey Badgley, the company's chief executive officer, said in the earnings report. "However, the current lack of new government orders, which were significant contributors to 2011's results, will impact us over the course of the year, barring any new orders."

Net income in the fourth quarter was $4.9 million, or 43 cents per share, an increase of 35.9 percent compared to net income of $3.6 million, or 30 cents per share, in the prior-year period.

Still, that missed analysts' expectations by 5 cents.

For the year, the company reported 2011 net income of $23 million, or $1.92 per share, more than double the net income of $11.7 million, or 96 cents per share, earned in 2010.

But the company completed its U.S. government orders in the fourth quarter of 2011. Without large government orders on the backlogs, Badgley warned, sales may slow.

The company is working on securing a French military contract and hopes to fill the hole left by the U.S. government.

"Over the long term, we are also targeting future growth initiatives in areas outside the domestic markets, particularly in Europe, as we look for new markets and distribution channels," Badgley said. "We are extremely well positioned and will remain aggressive in our efforts."