We shall consider domain walls in a relativistic field-theoretical model defined by the following Lagrangianwhere Φ is a single real scalar field, (η µν )=diag(-1,1,1,1) is the metric in Minkowski space-time, and λ, M are positive parameters. Euler-Lagrange equation corresponding to Lagrangian (1) has the particular time-independent solutionwhich describes a static, planar domain wall stretched along the x 3 = 0 plane. Here Φ 0 = M/(2 √ λ) denotes one of the two vacuum values of the field Φthe other one is equal to −Φ 0 . The parameter M can be identified with the mass of the scalar particle related to the field Φ. The corresponding Compton length l 0 = M −1 gives the physical length scale in the model. Energy density for the planar domain wall (2) is exponentially localised in a vicinity of the x 3 = 0 plane. The transverse width of the domain wall is of the order 2l 0 .The issue is time evolution of a non-planar domain wall. Such domain walls can be infinite, consider, e.g., locally deformed planar domain wall or a cylindrical domain wall. They can also be finite closed, e.g., like a sphere or a torus. We shall restrict our considerations to a single large, smooth 1