No, modernisation as a planning objective does not contradict employment generation. In fact, both modernisation and employment generation are positively correlated. By modernization we mean adoption of new technology to increase the production of goods and services. For example, a farmer can increase the output on the farm by using new seed varieties instead of using the old ones. Similarly, a factory can increase output by using a new type of machine. This does not cut down the employment generation opportunity rather this facilitate the manpower in their works. The only thing we need to train our human resources.
The use of modern technology and input will raise the productivity and, consequently, the income of the people that will further raise the demand for goods and services. In order to fulfill this increased demand, there will be more job opportunities that will lead more people to be hired and, hence, more employment opportunities will be generated. Hence, both modernisation and employment generation are not contradictory but are complementary to each other.