If you're under age 70 and want to work, you may have a better chance now that a new law extends the ban on age discrimination in employment from age 65 to 70.

Under the old law, employes were protected against age discrimination from age 40 to age 65. Now, age 70 is the top limit and, within two or three years, Congress may remove all upper limits.

The law makes a lot of sense. Employment practices should not be governed by age (or sex, race, religion, whatever), but should be governed by an individual's ability to do the job.

Not only are applicants for employment protected by the law, but all current employes under age 70 also are protected. No employer can force your age (if you're under age 70). For employes under 65 who are covered by a pension plan or company policy that previously required retirement at age 65, the new law is already in effect. For employes who are age 65 through 69, the law becomes effective Jan. 2, 1979. For employes under a collective bargaining contract, the law goes into effect Jan. 1, 1980, (or when the contract ends, whichever is first).

If you feel you have been denied employment because of your age or you have been let go (or forced to retire) because of your age, there are certain steps you can take to get the job, be reinstated or be paid compensatory damages.

But you must act quickly. There's deadline limit of 180 days for taking action. As soon as possible after you have been discriminated against, go to the nearest Wage and Hour Office of the Labor Department, Employment Standards Administration.

You must make a formal "charge" of discrimination, in writing, against the employer, and you must indicate your intention of suing (even if you never go through with it). This stakes your claim to a possible private lawsuit later on.

As a rule, officials in the Wage and Hour Office will have booklets that explain your rights. You'll be interviewed and your case will be investigated. The local office might try to use its conciliation powers to get your job back, persuade a potential employer to hire you, or get back wages.

It's very difficult to prove an individual case of age discrimination. In its investigation of the employer's hiring, firing and retiring practices, the government tries to come up with a "pattern" of discrimination.

While the government may help you get with you want through its conciliation powers or, eventually, be able to win what you want through court action, it may be a good idea to seek an attorney's help.

In your interviews with government officials at the Wage and Hour Office, you may learn that you have a good case. Any such information will be of value to your lawyer.

Naturally, hiring a lawyer and suing somebody costs money. But some lawyers might be enticed into taking your case on a contingency basis, getting a percentage of whatever money you win. This is especially true if a class action can be field against an employer on behalf of a number of employes who have been denied employment because of discrimination. And low-income people may qualify for free legal services.